TY - JOUR A1 - Kricheldorf, H. A1 - Weidner, Steffen T1 - Cyclic and linear poly(L-lactide)s by ring-expansion polymerization with Bu2SnO, Oct2SnO, and Bu2SnS N2 - To elucidate the usefulness of commercial Bu2SnO as catalyst for syntheses of linear and/or cyclic polylactides L-Lactide was polymerized in bulk with variation of the LA/Cat ratio, temperature and time. Based on a ring-expansion polymerization (REP) mechanism cyclic polylactides (PLAs) with weight average molecular weights in the range of 200,000–300,000 are obtained at the highest temperature (180 °C). Polymerizations at 150 °C yielded crystalline, mainly cyclic polylactides which, after annealing, showed high melting temperatures (up to 197.5 °C) and high crystallinities (>80%). Polymerization at 120 °C confirmed the trend towards more linear chains with lower temperatures but yielded extended-ring crystals showing a “saw-tooth pattern” in the mass spectra. Oct2SnO gave similar results as Bu2SnO. Bu2SnS proved a sluggish polymerization catalyst, but a good transesterification catalyst in solid PLA. KW - MALDI TOF MS KW - Biobased polymers KW - Polylactide KW - Ring-expansion polymerization PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584121 DO - https://doi.org/10.1002/pol.20230515 SN - 2642-4169 SP - 1 EP - 10 PB - Wiley CY - Hoboken, NJ AN - OPUS4-58412 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans R. A1 - Weidner, Steffen T1 - Ring-ring equilibration (RRE) of cyclic poly(L-lactide)s by means of cyclic tin catalysts N2 - With 2,2-dibutyl-2-stanna-1,3-dithiolane (DSTL) and 2-stanna-1,3-dioxa-4,5,6,7-dibenzoxepane (SnBiPh) as catalysts ring-expansion polymerizations (REP) were performed either in 2 M solution using three different solvents and two different temperatures or in bulk at 140 and 120 ◦C. A kinetically controlled rapid REP up to weight average molecular masses (Mẃs) above 300 000 was followed by a slower degradation of the molecular masses at 140 ◦C, but not at 120 ◦C Furthermore, a low molecular mass cyclic poly(L-lactide) (cPLA) with a Mn around 16 000 was prepared by polymerization in dilute solution and used as starting material for ring-ring equilibration at 140 ◦C in 2 M solutions. Again, a decrease of the molecular mass was detectable, suggesting that the equilibrium Mn is below 5 000. The degradation of the molecular masses via RRE was surprisingly more effective in solid cyclic PLA than in solution, and a specific transesterification mechanism involving loops on the surface of crystallites is proposed. This degradation favored the formation of extended-ring crystallites, which were detectable by a “saw-tooth pattern” in their MALDI mass spectra. KW - Organic Chemistry KW - Polymers and Plastics KW - MALDI-TOF MS KW - Materials Chemistry PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593819 DO - https://doi.org/10.1016/j.eurpolymj.2024.112765 SN - 0014-3057 VL - 206 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-59381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Kricheldorf, H. T1 - Transformation of poly(L-lactide) crystals composed of linear chains into crystals composed of cycles N2 - A poly(L-lactide) with a trifluoroethyl ester end group and an average degree of polymerization (DP) of 50 was synthesized by ROP of L-lactide initiated with trifluoroethanol. Small-angle X-ray scattering (SAXS) in combination with differential scanning calorimetry (DSC) measurements revealed an average crystal thickness of 13 nm, corresponding to 45 repeat units. This suggests that most crystallites were formed by extended PLA chains, and both flat surfaces were covered by CF3 groups. The crystalline PLAs were annealed at 140 or 160 °C in the presence of two catalysts: tin(II) 2-ethylhexanoate, (SnOct2) or dibutyltin bis(pentafluorophenoxide) (BuSnPhF). The chemical reactions, such as polycondensation and cyclization, proceeded in the solid state and were monitored by matrix-assisted laser desorption/ionization time-offlight (MALDI TOF) mass spectrometry and gel permeation chromatography (GPC) measurements. Under optimal conditions a large fraction of linear chains was transformed into crystallites composed of extended cycles. Additionally, MALDI TOF MS analysis of GPC fractions from samples annealed for 28 or 42 days detected chain elongation of the linear species up to a factor of 20. KW - Polylactide KW - MALDI-TOF MS KW - Crystalinity KW - Transesterification PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597250 DO - https://doi.org/10.1039/D3PY01370G SN - 1759-9954 VL - 15 IS - 12 SP - 1173 EP - 1181 PB - Royal Society for Chemistry AN - OPUS4-59725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chabbah, T. A1 - Chatti, S. A1 - Jaffrezic-Renault, N. A1 - Weidner, Steffen A1 - Marestin, C. A1 - Mercier, R. T1 - Impedimetric sensors based on diethylphosphonate-containingpoly(arylene ether nitrile)s films for the detection of lead ions N2 - This article describes the elaboration and characterization of diethylphosphonate-containing polymers coated electrodes as sensors for the detection of heavy metalstraces, by electrochemical impedance spectroscopy. Diethylphosphonate groupswere chosen as heavy metals binding sites. Two different series of polymers bearingthese anchoring groups were synthesized. Whereas the diethylphosphonate groupsare directly incorporated in the aromatic macromolecular chain in some polymers, analiphatic spacer is removing the chelating site from the polymer backbone in others.The influence of the macromolecular structure on the sensing response was studied,especially for the detection of Pb2+,Ni2+,Cd2+and Hg2+. Polymer P6, including thehigher amount of diethylphosphonate groups removed from the polymer chain by ashort alkyl spacer gave the higher sensitivity of detection of lead ions, with a detec-tion limit of 50 pM KW - Heavy metals KW - Phosphonate esters KW - Lead ions KW - MALDI TOF MS PY - 2023 DO - https://doi.org/10.1002/pat.6065 SN - 1042-7147 SP - 1 EP - 11 PB - John Wiley & Sons, Ltd AN - OPUS4-57356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Scholz, Philipp A1 - Jung, Christian A1 - Weidner, Steffen T1 - Thermo-Desorption Gas Chromatography-Mass Spectrometry for investigating the thermal degradation of polyurethanes N2 - Thermo-Desorption Gas Chromatography-Mass Spectrometry (TD-GC-MS) was used to investigate the thermal degradation of two different polyurethanes (PU). PU samples were heated at different heating rates and the desorbed products were collected in a cold injection system and thereafter submitted to GC-MS. Prospects and limitations of the detection and quantification of semi-volatile degradation products were investigated. A temperature dependent PU depolymerization was found at temperatures above 200 °C proved by an increasing release of 1,4-butanediol and methylene diphenyl diisocyanate (MDI) representing the main building blocks of both polymers. Their release was monitored quantitatively based on external calibration with authentic compounds. Size Exclusion Chromatography (SEC) of the residues obtained after thermodesorption confirmed the initial competitive degradation mechanism indicating an equilibrium of crosslinking and depolymerization as previously suggested. Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry of SEC fractions of thermally degraded PUs provided additional hints on degradation mechanism. KW - Thermo-desorption KW - Mass spectrometry KW - Polyurethanes KW - Thermal degradation PY - 2023 DO - https://doi.org/10.1039/D3AY00173C SN - 1759-9660 SP - 1 EP - 6 PB - Royal Society for Chemistry AN - OPUS4-57307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seifert, Stephan A1 - Weidner, Steffen A1 - Panne, Ulrich A1 - Kneipp, Janina T1 - Taxonomic relationship of pollen from MALDI TOF MS data using multivariate statistics N2 - Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been suggested as a promising tool for the investigation of pollen, but the usefulness of this approach for classification and identification of pollen species has to be proven by an application to samples of varying taxonomic relations. KW - MALDI mass spectrometry KW - Pollen KW - Multivariate statistics PY - 2015 DO - https://doi.org/10.1002/rcm.7207 SN - 0951-4198 SN - 1097-0231 VL - 29 SP - 1145 EP - 1154 PB - Wiley CY - Chichester AN - OPUS4-35296 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Zengchao A1 - Nirmalananthan-Budau, Nithiya A1 - Resch-Genger, Ute A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Separation of polystyrene nanoparticles bearing different carboxyl group densities and functional groups quantification with capillary electrophoresis and asymmetrical flow field flow fractionation N2 - Two sets of polystyrene nanoparticles (PSNPs) with comparable core sizes but different carboxyl group densities were made and separated using asymmetric flow field flow fractionation (AF4), capillary electrophoresis (CE), and the off-line hyphenation of both methods. Our results revealed the significant potential of two-dimensional off-line AF4-CE hyphenation to improve the separation and demonstrated for the first time, the applicability of CE to determine the functional group density of nanoparticles (NPs). Compared to the result acquired with conductometric titration, the result obtained with synthesized 100 nm sized PSNPs revealed only a slight deviation of 1.7%. Commercial 100 nm sized PSNPs yielded a deviation of 4.6 %. For 60 nm sized PSNPs, a larger deviation of 10.6 % between both methods was observed, which is attributed to the lower separation resolution. KW - Nanoparticle KW - A4F KW - Capillary electrophoresis KW - Carboxyl group PY - 2020 DO - https://doi.org/10.1016/j.chroma.2020.461392 VL - 1626 SP - 461392 PB - Elsevier B.V. AN - OPUS4-51080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Zengchao A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Separation of polystyrene nanoparticles with different coatings using two-dimensional off-line coupling of asymmetrical flow field flow fractionation and capillary electrophoresis N2 - The successful off-line coupling of asymmetrical flow field flow fractionation (AF4) and capillary electrophoresis (CE) for separation of nanoparticles (NPs) with different surface coatings was shown. We could successfully demonstrate that, in a certain NP size range, hyphenation of both techniques significantly improved the separation of differently coated NPs. Three mixtures of polystyrene nanoparticles (PS-NPs) with comparable core sizes but different coatings (no coating/carboxyl-coated) were studied. Separation in either method resulted in non-baseline resolved or non-separated peaks. In contrast, two-dimensional off-line coupling of AF4 and CE resulted in clearly separated regions in their 2 D plots in case of 20 and 50 nm particle mixtures, whereas the 100 nm NP mixture could not be separated at all. Various factors affecting the separation like hydrodynamic diameter or SDS concentration were discussed. KW - Capillary electrophoresis (CE) KW - Nanoparticles with same nominal diameter KW - Surface coating KW - Two-dimensional off-line coupling KW - Asymmetrical flow field flow fractionation (AF4) PY - 2019 DO - https://doi.org/10.1016/j.chroma.2019.01.056 VL - 1593 SP - 119 EP - 126 PB - Elsevier AN - OPUS4-47363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gabriel, Stefan A1 - Pfeifer, Dietmar A1 - Schwarzinger, C. A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Matrix-assisted laser desorption/ionization time-of-flight mass spectrometric imaging of synthetic polymer sample spots prepared using ionic liquid matrices N2 - RATIONALE Polymer sample spots for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) prepared by the dried-droplet method often reveal ring formation accompanied by possible segregation of matrix and sample molecules as well as of the polymer homologs itself. Since the majority of sample spots are prepared by this simple and fast method, a matrix or sample preparation method that excludes such segregation has to be found. METHODS Three different ionic liquid matrices based on conventionally used aromatic compounds for MALDI-TOF MS were prepared. The formation of ionic liquids was proven by 1H NMR spectroscopy. MALDI-Imaging mass spectrometry was applied to monitor the homogeneity. RESULTS Our results show a superior sample spot homogeneity using ionic liquid matrices. Spots could be sampled several times without visible differences in the mass spectra. A frequently observed loss of matrix in the mass spectrometer vacuum was not observed. The necessary laser irradiance was reduced, which resulted in less polymer fragmentation. CONCLUSIONS Ionic liquid matrices can be used to overcome segregation, a typical drawback of conventional MALDI dried-droplet preparations. Homogeneous sample spots are easy to prepare, stable in the MS vacuum and, thereby, improve the reproducibility of MALDI. PY - 2014 DO - https://doi.org/10.1002/rcm.6810 SN - 0951-4198 SN - 1097-0231 VL - 28 IS - 5 SP - 489 EP - 498 PB - Wiley CY - Chichester AN - OPUS4-30267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gabriel, Stefan A1 - Schwarzinger, C. A1 - Schwarzinger, B. A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Matrix segregation as the major cause for sample inhomogeneity in MALDI dried droplet spots N2 - The segregation in dried droplet MALDI sample spots was analyzed with regard to the matrix-to-sample ratio using optical microscopy, MALDI imaging mass spectrometry (MALDI MSI) and IR imaging spectroscopy. In this context, different polymer/matrix/solvent systems usually applied in the analysis of synthetic polymers were investigated. The use of typical matrix concentrations (10 mg mL-1) in almost every case resulted in ring patterns, whereas higher concentrated matrix solutions always led to homogeneous sample spot layers. The data revealed that segregation is predominantly caused by matrix transport in the drying droplet, whereas polymer segregation seems to be only secondary. KW - MALDI KW - Imaging MS KW - Matrix segregation KW - Dried droplet KW - Sample preparation KW - Polymers PY - 2014 DO - https://doi.org/10.1007/s13361-014-0913-0 SN - 1044-0305 VL - 25 IS - 8 SP - 1356 EP - 1363 PB - American Society for Mass Spectrometry CY - New York, NY AN - OPUS4-32582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Wachtendorf, Volker A1 - Panne, Ulrich A1 - Weidner, Steffen ED - Scholz, Philipp T1 - Degradation of MDI-based polyether and polyester-polyurethanes in various environments - Effects on molecular mass and crosslinking N2 - Size-exclusion chromatography (SEC) was used to monitor changes of the molecular masses of thermoplastic polyether – and polyester urethane (TPU) exposed to thermal, hydrolytic, and photo-oxidative (UV) Degradation conditions for several days. The thermal treatment was performed at elevated temperatures (100–200 °C) under oxidative (air) as well as non-oxidative (nitrogen) conditions to evaluate the specific influence of oxygen on the degradation. At higher temperatures (≥175 °C) a fast decrease of the molecular masses of both PU accompanied by a high degree of crosslinking was found. At lower temperatures (≤150 °C) the polymers remained widely unaffected by thermal degradation within the investigated degradation interval of up to two weeks. Surprisingly, the influence of oxygen (air) was found to be less distinct. In contrast to that, UV treatment at 25 °C at less than 10% rel. humidity (RH) resulted in a fast crosslinking, whereas the molecular masses of both PU decreased slower than for thermal treatments. The depth of penetration of the UV radiation was estimated using 3D printed PU samples with different thicknesses. Hydrolysis based degradation effects were less significant. Only slight molecular mass changes were detected at temperatures ≤80 °C within a time span of 14 days, while no crosslinking could be measured. Considering the degradation results at the investigated exposure parameters, it could be shown that esterbased PU in general exhibits a significant higher stability compared to ether-based materials. KW - Polyurethane KW - Thermal degradation KW - UV degradation KW - Molecular masses KW - Crosslinking PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0142941819302363 DO - https://doi.org/10.1016/j.polymertesting.2019.04.028 SN - 0142-9418 VL - 77 SP - 105881, 1 EP - 12 PB - Elsevier CY - Amsterdam AN - OPUS4-48619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sötebier, Carina A1 - Weidner, Steffen A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Bettmer, J. T1 - Separation and quantification of silver nanoparticles and silver ions using reversed phase high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry in combination with isotope dilution analysis N2 - A reversed phase high performance liquid chromatography coupled to an inductively coupled plasma mass spectrometer (HPLC-ICP-MS) approach in combination with isotope dilution analysis (IDA) for the separation and parallel quantification of nanostructured and ionic silver (Ag) is presented. The main focus of this work was the determination of the ionic Ag concentration. For a sufficient stabilization of the ions without dissolving the nanoparticles (NPs), the eluent had to be initially optimized. The determined Ag ion concentration was in a good agreement with results obtained using ultrafiltration. Further, the mechanism of the NP separation in the HPLC column was investigated. Typical size exclusion effects were found by comparing results from columns with different pore sizes. Since the recovery rates decreased with increasing Ag NP size and large Ag NPs did not elute from the column, additional interactions of the particles with the stationary phase were assumed. Our results reveal that the presented method is not only applicable to Ag NPs, but also to gold and polystyrene NPs. Finally, IDA-HPLC-ICP-MS experiments in single particle mode were performed to determine the particle cut-off size. The comparison with conventional spICP-MS experiments resulted in a similar diameter and particle size distribution. KW - ICP-MS KW - Silver nanoparticles KW - HPLC KW - Isotope dilution analysis KW - Field flow fractionation KW - Toxicology PY - 2016 DO - https://doi.org/10.1016/j.chroma.2016.09.028 SN - 0021-9673 VL - 1468 SP - 102 EP - 108 PB - Elsevier B.V. AN - OPUS4-38642 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Benjamin Christoph A1 - Seifert, Stephan A1 - Panne, Ulrich A1 - Kneipp, Janina A1 - Weidner, Steffen T1 - Matrix-assisted laser desorption/ionization mass spectrometric investigation of pollen and their classification by multivariate statistics N2 - RATIONALE A fast and reliable online identification of pollen is not yet available. The identification of pollen is based mainly on the evaluation of morphological data obtained by microscopic methods. METHODS Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) was applied to the analysis of extracts and milled pollen samples. The obtained MALDI data were explored for characteristic peak patterns which could be subjected to a multivariate statistical analysis. RESULTS Two sample preparation methods are presented, which require only minimal or no chemical extraction of the pollen. MALDI pollen spectra could be recorded showing various peak patterns. A multivariate statistics approach allowed the classification of pollen into clusters indicating similarities and differences between various species. CONCLUSIONS These results demonstrate the potential and the reliability of MALDI-TOF MS for the identification and, in combination with multivariate statistics, also for the classification of pollen. KW - MALDI TOF mass spectrometry KW - Pollen KW - Multivariate statistics PY - 2012 DO - https://doi.org/10.1002/rcm.6202 SN - 0951-4198 SN - 1097-0231 VL - 26 IS - 9 SP - 1032 EP - 1038 PB - Wiley CY - Chichester AN - OPUS4-25648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gabriel, Stefan A1 - Steinhoff, R.F. A1 - Pabst, M. A1 - Schwarzinger, C. A1 - Zenobi, R. A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Improved analysis of ultra-high molecular mass polystyrenes in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using DCTB matrix and caesium salts N2 - Rationale The ionization of polystyrenes in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is typically achieved by the use of silver salts. Since silver salts can cause severe problems, such as cluster formation, fragmentation of polymer chains and end group cleavage, their substitution by alkali salts is highly desirable. Methods The influence of various cations (Ag+, Cs+ and Rb+) on the MALDI process of polystyrene (PS) mixtures and high mass polystyrenes was examined. The sample preparation was kept as straightforward as possible. Consequently, no recrystallization or other cleaning procedures were applied. Results The investigation of a polystyrene mixture showed that higher molecular polystyrenes could be more easily ionized using caesium, rather than rubidium or silver salts. In combination with the use of DCTB as matrix a high-mass polymer analysis could be achieved, which was demonstrated by the detection of a 1.1 MDa PS. Conclusions A fast, simple and robust MALDI sample preparation method for the analysis of ultra-high molecular weight polystyrenes based on the use of DCTB and caesium salts has been presented. The suitability of the presented method has been validated by using different mass spectrometers and detectors. KW - MALDI KW - Mega-dalton KW - Ionization KW - Caesium KW - Polystyrene KW - DCTB PY - 2015 UR - http://onlinelibrary.wiley.com/doi/10.1002/rcm.7197/full DO - https://doi.org/10.1002/rcm.7197 SN - 0951-4198 SN - 1097-0231 VL - 29 IS - 11 SP - 1039 EP - 1046 PB - Wiley CY - Chichester AN - OPUS4-33191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Gabriel, Stefan A1 - Panne, Ulrich A1 - Schwarzinger, C. T1 - Entmischungsphänomene in der MALDI dried-droplet Probenpräparation und deren Vermeidung T2 - Anakon 2015 CY - Graz (Österreich) DA - 2015-03-23 PY - 2015 AN - OPUS4-33053 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sötebier, Carina A. A1 - Weidner, Steffen A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Bettmer, J. T1 - Separation and quantification of silver nanoparticles and silver ions using reversed phase high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry in combination with isotope dilution analysis N2 - A reversed phase high performance liquid chromatography coupled to an inductively coupled Plasma mass spectrometer (HPLC–ICP-MS) approach in combination with isotope dilution analysis (IDA) for the separation and parallel quantification of nanostructured and ionic silver (Ag) is presented. The main Focus of this work was the determination of the ionic Ag concentration. For a sufficient stabilization of the Ions without dissolving the nanoparticles (NPs), the eluent had to be initially optimized. The determined Ag ion concentration was in a good agreement with results obtained using ultrafiltration. Further, the mechanism of the NP separation in the HPLC column was investigated. Typical size exclusion effects were found by comparing results from columns with different pore sizes. Since the recovery rates decreased with increasing Ag NP size and large Ag NPs did not elute from the column, additional interactions of the particles with the stationary phase were assumed. Our results reveal that the presented method is not only applicable to Ag NPs, but also to gold and polystyrene NPs. Finally, IDA-HPLC-ICP-MS experiments in single particle mode were performed to determine the particle cut-off size. The comparison with conventional spICP-MS experiments resulted in a similar diameter and particle size distribution. KW - ICP-MS KW - Silver nanoparticles KW - Speciation KW - High performance liquid chromatography KW - Isotope dilution analysis PY - 2016 DO - https://doi.org/10.1016/j.chroma.2016.09.028 SN - 0021-9673 VL - 1468 SP - 102 EP - 108 AN - OPUS4-37652 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Gabriel, Stefan A1 - Panne, Ulrich A1 - Schwarzinger, C. A1 - Steinhoff, R. T1 - MALDI-TOF MS von ultra-hochmolekularen Polystyrolen mittels DCTB und Cäsium-Salzen T2 - 19. Kolloquium MALDI und Synthetische Polymere CY - Berlin DA - 2015-05-12 PY - 2015 AN - OPUS4-33055 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sötebier, Carina A1 - Bierkandt, Frank A1 - Rades, Steffi A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Sample loss in asymmetric flow field-flow fractionation coupled to inductively coupled plasma-mass spectrometry of silver nanoparticles N2 - In this work, sample losses of silver nanoparticles (Ag NPs) in asymmetrical flow field-flow fractionation (AF4) have been systematically investigated with the main focus on instrumental conditions like focusing and cross-flow parameters as well as sample concentration and buffer composition. Special attention was drawn to the AF4 membrane. For monitoring possible silver depositions on the membrane, imaging laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) was used. Our results show that the sample residue on the membrane was below 0.6% of the total injected amount and therefore could be almost completely avoided at low sample concentrations and optimized conditions. By investigation of the AF4 flows using inductively coupled plasma mass spectrometry (ICP-MS), we found the recovery rate in the detector flow under optimized conditions to be nearly 90%, while the cross-flow, slot-outlet flow and purge flow showed negligible amounts of under 0.5%. The analysis of an aqueous ionic Ag standard solution resulted in recovery rates of over 6% and the ionic Ag content in the sample was found to be nearly 8%. Therefore, we were able to indicate the ionic Ag content as the most important source of sample loss in this study. KW - Asymmetric flow filed-flow fractionation KW - ICP-MS KW - Nanoparticles KW - Sample loss KW - Quantification PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-336171 DO - https://doi.org/10.1039/c5ja00297d SN - 0267-9477 SN - 1364-5544 VL - 30 IS - 10 SP - 2214 EP - 2222 PB - Royal Society of Chemistry CY - London AN - OPUS4-33617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Knappe, Patrick A1 - Panne, Ulrich T1 - MALDI-TOF imaging mass spectrometry of artifacts in 'dried droplet' polymer samples N2 - Matrix-assisted laser desorption/ionization-timeof-flight (MALDI-TOF) imaging of polystyrenes with various molecular masses was applied to study spatial molecular mass distribution of polymers in sample spots prepared by the 'dried droplet' method. When different solvents and target surfaces were examined, a segregation of single homologous polymers was observed depending upon the evaporation rate of the solvent. For the observed Patterns left by the evaporating droplet, a hypothesis is offered taking into account different hydrodynamic interactions and diffusion. The results illustrate that spot preparation using the conventionally 'dried droplet' method is prone to artifacts and should be avoided for reliable and reproducible MALDI mass spectrometry experiments with regards to the Determination of molecular masses and mass distributions. KW - MALDI KW - Mass spectrometry imaging KW - Polymer KW - Droplet PY - 2011 DO - https://doi.org/10.1007/s00216-011-4773-1 SN - 1618-2642 SN - 1618-2650 VL - 401 IS - 1 SP - 127 EP - 134 PB - Springer CY - Berlin AN - OPUS4-24538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leiterer, Jork A1 - Panne, Ulrich A1 - Thünemann, Andreas A1 - Weidner, Steffen T1 - Container-less polymerization in acoustically levitated droplets: an analytical study by GPC and MALDI-TOF mass spectrometry N2 - Molecular masses and end groups of polystyrene (PS) formed in a novel container-less polymerization strategy, based on levitated droplets in an acoustic trap, were determined by Gel Permeation Chromatography (GPC) and Matrix-assisted Laser Desorption/Ionization Time of Flight Mass spectrometry (MALDI-TOF MS). KW - Ultraschallfalle KW - MALDI Massenspektrometrie KW - Polymerisation PY - 2011 DO - https://doi.org/10.1039/c0ay00390e SN - 1759-9660 SN - 1759-9679 VL - 3 IS - 1 SP - 70 EP - 73 PB - RSC Publ. CY - Cambridge AN - OPUS4-23655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. A1 - Weidner, Steffen T1 - Low Molar Mass Cyclic Poly(L-lactide)s: Separate Transesterification Reactions of Cycles and Linear Chains in the Solid State N2 - L-Lactide (LA) was polymerized with neat tin(II) 2-ethylhexanoate (SnOct2) in toluene at 115 °C at low concentration with variation of the LA/Cat ratio. Cyclic polylactides (cPLAs) with number average molecular weights (Mn) between 7 000 and 17 000 were obtained. MALDI-TOF mass spectrometry also revealed the formation of a few percent of linear chains. Crystalline cPLAs with Mn around 9 000 and 14 000 were annealed at 140 °C in the presence of ScOct2 or dibutyl-2-stanna-1,3-dithiolane (DSTL). Simultaneously, crystallites of extended linear chains and crystallites of extended cycles were formed regardless of the catalyst, indicating that transesterification reaction proceeded different for linear chains and for cycles, governed by thermodynamic control. The formation of extended chain crystallites with low dispersity indicates the existence of symproportionation of short and long chains. A complementary experiment was carried out with a PLA ethyl ester composed mainly of linear chains with a small fraction of cycles KW - Polylactide KW - MALDI-TOF MS KW - Annealing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606228 DO - https://doi.org/10.1039/D4SM00567H SN - 1744-6848 SP - 1 EP - 12 PB - Royal Society of Chemistry (RSC) AN - OPUS4-60622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Kricheldorf, H. T1 - Polymer mass spectrometry at BAM with special emphasis on MALDI and ESI N2 - Since its introduction mass spectrometric techniques like Matrix-assisted Laser Desorption/ionization (MALDI) and Electrospray Ionization (ESI) have become indispensable for synthetic polymer analyses. Ideally, various polymer properties (monomer structure, masses, mass distribution, end groups) can be determined simultaneously. However, in real life these experiments are always affected by important structural parameters and instrumental limitations. A short introduction focussing on latest findings with respect to ionisation principles and mechanisms will be given. Recent results from our group will be presented and efforts to avoid common drawbacks of polymer mass spectrometry will be discussed. In this regard, MALDI - Imaging mass spectrometry and the 2D hyphenation of MS with different chromatographic separation techniques were especially useful, since they can provide additional information and reduce the complexity of polymer analyses. T2 - 21. European Symposium on Polymer Spectroscopy CY - Linz, Austria DA - 13.01.2020 KW - Mass spectrometry KW - MALDI-TOF MS KW - ESI-TOF MS KW - Polymer PY - 2020 AN - OPUS4-50260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Falkenhagen, Jana A1 - Kricheldorf, H. R. T1 - Polycondensations and Cyclization of Poly(L-lactide) Ethyl Esters in the Solid State N2 - The usefulness of seven different Tin catalysts, Bismuth subsalicylate and Titan tetra(ethoxide) for the polycondensation of ethyl L-lactate (ELA) was examined at 150 °C/6 d. Dibutyltin bis(phenoxides) proved to be particularly effective. Despite the low reactivity of ELA, weight average molecular masses (Mw) up to 12 500 were found along with partial crystallization. Furthermore, polylactides (PLAs) of similar molecular masses were prepared via ELA-initiated ROPs of L-lactide by means of the four most effective polycondensation catalysts. The crystalline linear PLAs were annealed at 140 or 160 °C in the presence of these catalysts. The consequences of the transesterification reactions in the solid PLAs were studied by means of matrix-assisted laser desorption/ionization (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC) and small-angle X-ray scattering (SAXS). The results indicate that polycondensation and formation of cycles proceed in the solid state via formation of loops on the surface of the crystallites. In summary, five different transesterification reactions are required to explain all results. KW - Polylactide KW - MALDI-TOF MS KW - Crystalinity PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592934 DO - https://doi.org/10.1039/d3py01232h SN - 1759-9962 VL - 15 IS - 2 SP - 71 EP - 82 PB - RSC Publ. CY - Cambridge AN - OPUS4-59293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Weidner, Steffen A1 - Falkenhagen, Jana ED - Li, L. T1 - LC-MALDI MS for polymer characterization KW - Mass spectrometry KW - Polymers PY - 2010 SN - 978-0-471-77579-9 N1 - Serientitel: Chemical analysis: a series of monographs on analytical chemistry and its applications – Series title: Chemical analysis: a series of monographs on analytical chemistry and its applications VL - 175 IS - Chapter 11 SP - 247 EP - 265 PB - John Wiley & Sons AN - OPUS4-26406 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Polymer Characterization by LC / MALDI-MS Coupling T2 - Vortragstagung "Funktionspolymere für Systemlösungen" CY - Darmstadt, Germany DA - 2002-03-18 PY - 2002 AN - OPUS4-1805 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Much, Helmut A1 - Krüger, Ralph-Peter A1 - Friedrich, Jörg Florian T1 - Determination of chemical and molecular-weight distributions of heterogeneous polymers by means of MALDI-MS coupled with chromatography T2 - 219th ACS national meeting CY - San Francisco, CA, USA DA - 2000-03-26 PY - 2000 SN - 0032-3934 VL - 41 IS - 1 SP - 655 EP - 656 PB - American Chemical Society CY - Newark, NJ AN - OPUS4-2169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Schulz, Günter A1 - Weidner, Steffen T1 - Polymer characterization by LC / MALDI-MS coupling T2 - Bayreuther Polymer Symposium 2001 CY - Bayreuth, Germany DA - 2001-09-16 PY - 2001 CY - Bayreuth AN - OPUS4-2256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Friedrich, Jörg Florian A1 - Schulz, Günter A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Weidner, Steffen T1 - Liquid Adsorption Chromatography near Critical Conditions of Adsorption coupled with Matrix-assisted Laser Desorption/Ionization Mass Spectrometry N2 - Chemical heterogeneities and molecular weight distributions of poly(ethylene oxide) (PEO)-co-polymethylene (PM) model oligomers, which are relevant to the synthesis of commonly used tensides, were investigated. For analytical characterization, the well-known principle of liquid adsorption chromatography at 'critical conditions' (LACCC) was modified. Near the critical conditions of adsorption of the PEO unit, e.g., at slight adsorption conditions of PM, the copolymers could be separated according to their PM chain length. The eluates were separated and single fractions of each peak were continuously transferred onto the MALDI target by means of a commercially available device. Simultaneously, the MALDI matrix solution was continuously added with a second pump. This procedure offers the possibility of the formation of homogeneous matrix-polymer textures. By MALDI-MS a complete characterization of the chemical composition (PEO and PM chain length) of each peak could be achieved. The obtained MALDI mass spectra of the eluates at different retention times could be used for the molecular weight calibration of the LAC system. In this way, an additional application of SEC, as in conventional 2D-chromatography, was avoided by using the MALDI method as quasi chromatographic separation KW - Liquid adsorption chromatography KW - Matrix-assisted laser desorption KW - Ionization mass spectrometry KW - Coupling methods KW - MALDI PY - 2000 DO - https://doi.org/10.1080/10236660008034644 SN - 1023-666X SN - 1563-5341 VL - 5 SP - 549 EP - 562 PB - Gordon and Breach Publ. CY - Amsterdam AN - OPUS4-2168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hoskins, Jessica A1 - Falkenhagen, Jana A1 - Weidner, Steffen ED - Udomkichdecha, W. ED - Böllinghaus, T. ED - Manonukul, A. ED - Lexow, J. T1 - Characterization of randomly branched polymers utilizing liquid chromatography and mass spectrometry N2 - Branching in polymers is an important way to modify the materials properties, however the characterization of random branching in polymeric materials is a challenge in polymer analysis. In this work, liquid adsorption chromatography methods are developed for a commercially available hyperbranched polyester (Boltorn™). This Chromatographie techniques was then coupled to offline MALDI-TOF MS analysis, a first in the analysis of randomly branched polymers. The coupling of these two techniques provides superior MALDI-TOF spectra, enabling the easy identification of structural subdistributons based on theoretical molecular weight. Detailed analysis of the MALDI-TOF spectra shows that these Chromatographie conditions separate cyclic Boltorn polymers (with no core molecule) from non-cyclic polymers (with core molecule), and these are the only two architectures observed. MALDI MS also confirms that the Chromatographie Separation mode is adsorption, but further analysis is needed to determine if there is a Separation by degree of branching. KW - Hyperbranched polyesters KW - Polymer mass spectrometry KW - Polymer chromatography KW - Liquid adsorption chromatography KW - MALDI-TOF MS KW - Carbon capture KW - Climate change KW - Lubricant KW - Micro manufacturing KW - Multiphysics simulations KW - WMRIF PY - 2014 SN - 978-3-319-11339-5 SN - 978-3-319-11340-1 SP - 1 EP - 10 PB - Springer AN - OPUS4-32519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - Reversible Polycondensations outside the Jacobson-Stockmayer Theory and a New Concept of Reversible Polycondensations N2 - L-Lactide was polymerized with tin(II)acetate, tin(II)2-ethyl hexanoate, diphenyltin dichloride and dibutyltin bis(pentafluorophenoxide) at 130 °C in bulk. When an alcohol was added as initiator, linear chains free of cycles were formed having a degree of polymerization (DP) according to the lactide/initiator (LA/In) ratio. Analogous polymerizations in the absence of an initiator yielded high molar mass cyclic polylactides. Quite similar results were obtained when ε-caprolactone was polymerized with or without initiator. Several transesterification experiments were conducted at 130 °C, either with polylactide or poly(ε-caprolactone) indicating that several transesterification mechanisms are operating under conditions that do not include formation of cycles by back-biting. Furthermore, reversible polycondensations (revPOCs) with low or moderate conversions were found that did not involve any kind of cyclization. Therefore, These results demonstrate the existence of revPOCs, which do neither obey the theory of irreversible polycondensation as defined by Flory nor the hypothesis of revPOCs as defined by Jacobson and Stockmayer. A new concept encompassing any kind of revPOCs is formulated in the form of a “polycondensation triangle”. KW - Polylactide KW - MALDI-TOF MS KW - Polycondensation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530831 DO - https://doi.org/10.1039/d1py00704a VL - 12 IS - 35 SP - 5003 EP - 5016 PB - Royal Society for Chemistry AN - OPUS4-53083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Falkenhagen, Jana A1 - Kricheldorf, H. R. T1 - SnOct2-catalyzed and alcohol-initiated ROPs of L-lactide – About the influence of initiators on chemical reactions in the melt and the solid state N2 - SnOct2 (Sn(II) 2-ethylhexanoate) catalyzed ROPs of L-lactide were performed in bulk with eight different alcohols as initiators. The time was varied between 1 h and 24 h for all initiators. For two initiators the temperature was also lowered to 115 ◦C. Even-numbered chains were predominantly formed in all polymerizations at short times, but the rate of transesterification (e.g. even/odd equilibration) and the molecular weight distribution were found to depend significantly on the nature of the initiator. Observed transesterification reactions also continued in solid poly (L-lactide), and with the most active initiator, almost total equilibration was achieved even at 130 ◦C. This means that all chains including those of the crystallites were involved in transesterification reactions proceeding across the flat surfaces of the crystallites. The more or less equilibrated crystalline polylactides were characterized by DSC and SAXS measurements with regard to their melting temperature (Tm), crystallinity and crystal thickness. KW - Polylactide KW - MALDI-TOF MS KW - Crystallization KW - Catalysts KW - SAXS PY - 2021 DO - https://doi.org/10.1016/j.eurpolymj.2021.110508 VL - 153 SP - 110508 PB - Elsevier Ltd. AN - OPUS4-52633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Bressler, I. T1 - Copolymer composition determined by LC-MALDI-TOF MS coupling and 'MassChrom2D' data analysis N2 - The MALDI-TOF MS analysis of copolymers very often results in complex spectra. A chromatographic separation/fractionation prior to the MALDI investigation can be advantageous since the MALDI mass spectra of fractions very often reveal well-resolved peaks of distinguishable copolymer series. For this purpose, different modes of chromatography have been applied. Chromatographic runs were transferred to MALDI targets utilizing a combined air/electrospray deposition device. Using the new MassChrom2D software, fraction-dependent 2D copolymer compositions plots were obtained providing additional information on the chromatographic mode, and enabling fast modification of conditions to increase separation. KW - Copolymer composition KW - Chromatography KW - Coupling KW - MALDI-TOF mass spectrometry PY - 2012 DO - https://doi.org/10.1002/macp.201200169 SN - 1022-1352 SN - 1521-3935 VL - 213 IS - 22 SP - 2404 EP - 2411 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Breßler, Ingo A1 - Falkenhagen, Jana T1 - MassChrom2D - a software that combines chromatographic separation and mass spectrometric identification to analyze the composition of copolymers T2 - 60th ASMS Conference on Mass Spectrometry and Allied Topics CY - Vancouver, Canada DA - 2012-05-20 PY - 2012 AN - OPUS4-25954 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Falkenhagen, Jana A1 - Weidner, Steffen ED - Barner-Kowollik, C. ED - Gründling, T. ED - Falkenhagen, Jana ED - Weidner, S. T1 - Hyphenated techniques KW - MALDI KW - Chromatography KW - Coupling techniques PY - 2012 SN - 978-3-527-32924-3 SP - 209 EP - 235 PB - Wiley-VCH Verlag GmbH & Co. KGaA AN - OPUS4-26395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, J.L. A1 - Lutomski, C.A. A1 - El-Baba, T.J. A1 - Siriwardena-Mahanama, B.N. A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Allen, M. J. A1 - Trimpin, S. T1 - Matrix-assisted ionization-ion mobility spectrometry-mass spectrometry: Selective analysis of a europium-PEG complex in a crude mixture N2 - The analytical utility of a new and simple to use ionization method, matrix-assisted ionization (MAI), coupled with ion mobility spectrometry (IMS) and mass spectrometry (MS) is used to characterize a 2-armed europium(III)-containing poly(ethylene glycol) (Eu-PEG) complex directly from a crude sample. MAI was used with the matrix 1,2-dicyanobenzene, which affords low chemical background relative to matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI). MAI provides high ion abundance of desired products in comparison to ESI and MALDI. Inductively coupled plasma-MS measurements were used to estimate a maximum of 10% of the crude sample by mass was the 2-arm Eu-PEG complex, supporting evidence of selective ionization of Eu-PEG complexes using the new MAI matrix, 1,2-dicyanobenzene. Multiply charged ions formed in MAI enhance the IMS gas-phase separation, especially relative to the singly charged ions observed with MALDI. Individual components are cleanly separated and readily identified, allowing characterization of the 2-arm Eu-PEG conjugate from a mixture of the 1-arm Eu-PEG complex and unreacted starting materials. Size-exclusion chromatography, liquid chromatography at critical conditions, MALDI-MS, ESI-MS, and ESI-IMS-MS had difficulties with this analysis, or failed. KW - Matrix-assisted ionization ion mobility spectrometry mass spectrometry KW - Europium KW - Poly(ethylene glycol) KW - Size-exclusion chromatography KW - Liquid chromatography at critical conditions KW - Electrospray ionization KW - Matrix-assisted laser desorption/ionization KW - Inductively coupled plasma-mass spectrometry KW - ESI KW - MALDI KW - SEC PY - 2015 DO - https://doi.org/10.1007/s13361-015-1233-8 SN - 1044-0305 VL - 26 IS - 12 SP - 2086 EP - 2095 PB - Elsevier CY - New York, NY AN - OPUS4-35283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baumann, Maria A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Wold, C. A1 - Uliyanchenko, E. T1 - Characterization of copolymers of polycarbonate and polydimethylsiloxane by 2D chromatographic separation, MALDI-TOF mass spectrometry, and FTIR spectroscopy N2 - The structure and composition of polycarbonate polydimethylsiloxane copolymer (PC-co-PDMS) was investigated by applying various analytical approaches including chromatographic separation methods, spectrometric, and spectroscopic detection techniques. In particular, size exclusion chromatography (SEC) and liquid adsorption chromatography operating at different conditions (e.g. using gradient solvent systems) were used to achieve separations according to molar mass and functionality distribution. The coupling of both techniques resulted in fingerprint two-dimensional plots, which could be used to easily compare different copolymer batches. Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry was applied for structural investigations. The different ionization behavior of both comonomers, however, strongly limited the applicability of this technique. In contrast to that, Fourier-transform Infrared (FTIR) spectroscopy could be used to quantify the amount of PDMS in the copolymer at different points in the chromatogram. The resulting methodology was capable of distinguishing PC-co-PDMS copolymer from PC homopolymer chains present in the material. KW - FTIR KW - Liquid chromatography KW - Mass spectrometry KW - Gradient elution KW - Polycarbonate-co-dimethylsiloxane copolymer PY - 2020 DO - https://doi.org/10.1080/1023666X.2020.1820170 VL - 25 IS - 7 SP - 1 EP - 12 PB - Taylor & Francis AN - OPUS4-51369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Detection limits of matrix-assisted laser desorption/ionisation mass spectrometry coupled to chromatography - a new application of solvent-free sample preparation N2 - The detection limits of matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) by semi-online coupling with chromatography were investigated using various mixtures of polyethylene oxides (PEOs) with different end groups. In contrast to the common dried-droplet sample preparation technique, which results in an inhomogeneous sample-to-matrix ratio within the MALDI spot, the used coupling technique offers a very high reproducibility combined with surpassing sensitivity of a few femtograms over a broad range of sample-to-matrix ratios. These results are in correlation with the results of the recently established solvent-free MALDI-TOFMS method utilising the grinding approach and are also of assistance towards the more theoretical aspect of MALDI that suggests that there is no necessity for an analyte incorporation into a matrix crystal for excellent matrix-assistance. PY - 2005 DO - https://doi.org/10.1002/rcm.2256 SN - 0951-4198 SN - 1097-0231 VL - 19 IS - 24 SP - 3724 EP - 3730 PB - Wiley CY - Chichester AN - OPUS4-11859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Just, Ulrich T1 - MALDI-TOF mass spectrometry for the analysis of synthetic polymers T2 - eingelad. Vortrag im National Institute for Advanced Industrial Science and Technology (AIST) CY - Tsukuba, Japan DA - 2006-09-14 PY - 2006 AN - OPUS4-13827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Schulze, Rolf-Dieter A1 - Thünemann, Andreas T1 - Sample spot heterogeneity investigated by MALDI-imaging mass spectrometry T2 - 57th ASMS Conference On Mass Spectrometry and Allied Topics CY - Philadelphia, PA, USA DA - 2009-05-31 PY - 2009 AN - OPUS4-19191 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Schulze, Rolf-Dieter A1 - Thünemann, Andreas T1 - Sample spot heterogeneity investigated by MALDI-imaging mass spectrometry T2 - 18th International Mass Spectrometry Conference CY - Bremen, Germany DA - 2009-08-30 PY - 2009 AN - OPUS4-19375 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - Imaging mass spectrometry for examining localization of polymeric composition in matrix-assisted laser desorption/ionization samples N2 - The localization of polymeric composition in samples prepared for matrix-assisted laser desorption/ionization (MALDI) analysis has been investigated by imaging mass spectrometry. Various matrices and solvents were used for sample spot preparation of a polybutyleneglycol (PBG 1000). It was shown that in visibly homogeneous spots, prepared using the dried droplet method, separation between matrix and polymer takes place. Moreover, using -cyano-4-hydroxycinnamic acid (CCA) as matrix and methanol as solvent molecular mass separation of the polymer homologues in the spots was detectable. In contrast to manually spotted samples, dry spray deposition results in homogeneous layers showing no separation effects. KW - Imaging KW - MALDI TOF Massenspektrometrie KW - Polymere PY - 2009 DO - https://doi.org/10.1002/rcm.3919 SN - 0951-4198 SN - 1097-0231 VL - 23 IS - 5 SP - 653 EP - 660 PB - Wiley CY - Chichester AN - OPUS4-19622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Schulze, Rolf-Dieter T1 - Sample spot heterogeneity investigated by MALDI-imaging mass spectrometry T2 - 18th International Mass Spectrometry Conference CY - Bremen, Germany DA - 2009-08-30 PY - 2009 AN - OPUS4-19989 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenhagen, Jana A1 - Weidner, Steffen T1 - Determination of critical conditions of adsorption for chromatography of polymers N2 - Liquid chromatography (LC) at critical conditions of adsorption was used to separate various poly(ethylene oxides), poly(propylene oxides) and their copolymers. For the first time, the determination of the critical conditions by means of Ultra Performance Liquid Chromatography (UPLC) coupled to Electrospray Ionization Time-of-flight Mass Spectrometry (ESI-TOF MS) is reported. In contrast to established, mostly laborious routines to find suitable chromatographic separation conditions, this coupling enables a very fast adjustment of parameters. Similar to LC Matrix-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (LC/MALDI MS) coupling, a two-dimensional analysis of homo- and copolymers regarding its functionality type and molecular weight distribution, as well as copolymer composition, can be performed simultaneously. Furthermore, there is no need for using polymer standards for the determination of critical conditions or Size Exclusion Chromatography calibration. KW - Polymere KW - UPLC KW - ESI-Massenspektrometrie KW - Kopplung PY - 2009 DO - https://doi.org/10.1021/ac8019784 SN - 0003-2700 SN - 1520-6882 VL - 81 IS - 1 SP - 282 EP - 287 PB - American Chemical Society CY - Washington, DC AN - OPUS4-19619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - LC-MALDI-TOF imaging MS: a new approach in combining chromatography and mass spectrometry of copolymers N2 - A new approach that utilizes MALDI-TOF imaging mass spectrometry as a new detector for polymer chromatography is presented. For the first time, the individual retention behavior of single structural units of polyethylene oxide (PEO)/polypropylene oxide (PPO) copolymers and changes of the copolymer composition could be monitored. Composition specific calibration curves could be easily obtained by displaying the copolymer ion intensity data. This approach provides completely new insights in the chromatographic principle of copolymer separation and could be used to easily modify and adapt conditions for separation. In combination with electrospray deposition, homogeneous sample/matrix traces of surprisingly high spatial resolution could be obtained. KW - MALDI KW - Massenspektrometrie KW - Imaging KW - Chromatographie KW - Polymere PY - 2011 DO - https://doi.org/10.1021/ac202380n SN - 0003-2700 SN - 1520-6882 VL - 83 IS - 23 SP - 9153 EP - 9158 PB - American Chemical Society CY - Washington, DC AN - OPUS4-24974 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmid, C. A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Barner-Kowollik, C. T1 - In-depth LCCC-(GELC)-SEC characterization of ABA block copolymers generated by a mechanistic switch from RAFT to ROP N2 - A recently introduced procedure involving a mechanistic switch from reversible addition–fragmentation chain transfer (RAFT) polymerization to ring-opening polymerization (ROP) to form diblock copolymers is applied to synthesize ABA (star) block copolymers. The synthetic steps include the polymerization of styrene with R-group designed RAFT agents, the transformation of the thiocarbonyl thio end groups into OH functionalities, and their subsequent chain extension by ROP. The obtained linear ABA poly(ε-caprolactone)-block-poly(styrene)-block-poly(ε-caprolactone) (pCL-b-pS-b-pCL) (12 500 g mol–1 ≤ Mn ≤ 33 000 g mol–1) and the star-shaped poly(styrene)-block-poly(ε-caprolactone) (Mn = 36 000 g mol–1) copolymers were analyzed by size exclusion chromatography (SEC), nuclear magnetic resonance (NMR), infrared (IR) spectroscopy, and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The focus of the current study is on the detailed characterization of the ABA (star) block polymers via multidimensional chromatographic techniques specifically high performance liquid chromatography coupled to size exclusion chromatography (HPLC-SEC). In particular, we demonstrate the first time separation of poly(ε-caprolactone) (pCL) homopolymer and additionally poly(styrene) (pS) from the ABA poly(ε-caprolactone)-b-poly(styrene)-b-poly(ε-caprolactone) and star-shaped poly(styrene)-b-poly(ε-caprolactone) block copolymer utilizing critical conditions (CC) for pCL with concomitant gradient elution liquid chromatography (GELC). KW - Two-dimensional-liquid chromatography (2D-LC) KW - Liquid chromatography under critical conditions (LCCC) KW - Gradient elution liquid chromatography (GELC) KW - Soft ionization mass spectrometry (ESI, MALDI) KW - Reversible addition fragmentation chain transfer (RAFT) KW - Ring opening polymerization (ROP) PY - 2012 DO - https://doi.org/10.1021/ma2022452 SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 1 SP - 87 EP - 99 PB - American Chemical Society CY - Washington, DC AN - OPUS4-25464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - Hyphenated coupling methods for polymer characterization and identification T2 - Dutch Polymer Workshop CY - Jena, Germany DA - 2013-12-09 PY - 2013 AN - OPUS4-30268 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - The role of transesterifications in reversible polycondensations and a reinvestigation of the Jacobson-Beckmann-Stockmayer experiments N2 - The polycondensations of adipic acid and 1,10-decanediol catalyzed by toluene sulfonic acid (TSA) were reinvestigated using MALDI TOF mass spectrometry and NMR spectroscopy. Unexpected reactions of TSA were detected along with incomplete conversion of the monomers. Furthermore, transesterification reactions of end-capped poly(1,10-decanediol adipate) and end-capped poly(ε-caprolactone) catalyzed by TSA were studied. Despite the quite different (ionic) reaction mechanisms, it was found that for polycondensations performed in bulk intermolecular transesterification is more efficient than the intramolecular “back-biting”; this scenario was not considered in the Jacobson–Stockmayer theory of reversible polycondensations. These results also confirm that the Jacobson–Stockmayer explanation of reversible polycondensations solely on the basis of ring chain equilibration is not only devoid of any experimental evidence, but also in contradiction to the results elaborated in this work. KW - Polylactide KW - MALDI-TOF MS KW - Polycondensation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543402 DO - https://doi.org/10.1039/d1py01679b SN - 1759-9962 SP - 1 EP - 9 PB - RSC Publ. CY - Cambridge AN - OPUS4-54340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Wachtendorf, Volker A1 - Elert, Anna Maria A1 - Falkenhagen, Jana A1 - Becker, Roland A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Tschiche, Harald A1 - Reinsch, Stefan A1 - Weidner, Steffen ED - Scholz, Philipp T1 - Analytical toolset to characterize polyurethanes after exposure to artificial weathering under systematically varied moisture conditions N2 - Polyether and -ester urethanes (PU) were exposed to artificial weathering at 40 °C and artificial UV radiation in a weathering chamber. In 3 parallel exposures, humidity was varied between dry, humid, and wet conditions. Material alteration was investigated by various analytical techniques like size exclusion chromatography (SEC), liquid chromatography-infrared spectroscopy (LC-FTIR), thermal-desorption gas chromatography-mass spectrometry (TD-GC-MS), fluorescence mapping and dynamic mechanical analysis (DMA). Our results show that depending on the weathering conditions, different degradation effects can be observed. By means of SEC an initial strong decrease of the molar masses and a broadening of the mass distributions was found. After a material dependent time span this was followed by a plateau where molar mass changes were less significant. A minor moisture-dependent degradation effect was only found for polyester PU. Fluorescence measurements on two materials revealed an increase in the luminescence intensity upon weathering process reaching a saturation level after about 500 h. The changes in the optical properties observed after different exposure conditions and times were very similar. The TD-GC-MS data showed the fate of the stabilizers and antioxidant in the course of weathering. LC-FTIR measurements revealed a change in peak intensities and the ratio of urethane and carbonyl bands. KW - Polyurethane KW - Artificial weathering KW - Moisture KW - Crosslinking KW - Degradation PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0142941819303708 DO - https://doi.org/10.1016/j.polymertesting.2019.105996 SN - 0142-9418 VL - 78 SP - 105996, 1 EP - 9 PB - Elsevier CY - Amsterdam AN - OPUS4-48625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fandrich, Nick A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Staal, B. A1 - Thünemann, Andreas A1 - Laschewsky, A. T1 - Characterization of new amphiphilic block copolymers of N-vinylpyrrolidone and vinyl acetate, 2 - chromatographic separation and analysis by MALDI-TOF and FT-IR coupling N2 - PVP-block-PVAc block copolymers were synthesized by controlled radical polymerization applying a RAFT/MADIX system and were investigated by HPLC and by coupling of chromatography to FT-IR spectroscopy and MALDI-TOF MS. Chromatographic methods (LACCC and gradient techniques) were developed that allowed a separation of block copolymers according to their repeating units. The results of the spectroscopic and spectrometric analysis clearly showed transfer between radicals and process solvent. With the use of hyphenated techniques differences between main and side products were detected. In agreement with previously published results, obtained by NMR, SEC, static light scattering and MALDI-TOF MS, our data proved a non-ideal RAFT polymerization. KW - Amphiphiles KW - Block copolymers KW - Liquid chromatography KW - MALDI KW - Reversible addition fragmentation chain transfer (RAFT) KW - Liquid adsorption chromatography at critical conditions KW - Gradient chromatography KW - MALDI-TOF mass spectrometry KW - Hyphenated techniques KW - Mechanism of polymerization PY - 2010 DO - https://doi.org/10.1002/macp.201000044 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 15 SP - 1678 EP - 1688 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Maltsev, Sergey A1 - Sauerland, V. A1 - Rinken, M. T1 - A novel software tool for copolymer characterization by coupling of liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry N2 - The results of copolymer characterization by coupling of chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques and subsequent calculation of copolymer composition using a novel software tool MassChrom2D are presented. For high-resolution mass analysis copolymer samples were fractionated by means of liquid adsorption chromatography (LAC). These fractions were investigated off-line by MALDI-TOF MS. Various mono-n-butyl ethers of polyethylene oxide-polypropylene oxide copolymers (PEO-co-PPO) were investigated. As well as the copolymer composition presented in two-dimensional plots, the applied approach can give additional hints on specific structure-dependent separation conditions in chromatography. KW - Copolymeranalytik KW - MALDI KW - Software KW - MS/MS KW - Kopplungsmethoden PY - 2007 DO - https://doi.org/10.1002/rcm.3146 SN - 0951-4198 SN - 1097-0231 VL - 21 IS - 16 SP - 2750 EP - 2758 PB - Wiley CY - Chichester AN - OPUS4-17723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Krüger, Rita A1 - Falkenhagen, Jana A1 - Friedrich, Jörg F. A1 - Gerstung, Vanessa A1 - Just, Ulrich A1 - Krüger, Ralph-Peter A1 - Much, Helmut A1 - Schulz, Günter T1 - Neue Wege zur analytischen Charakterisierung komplexer Polymersysteme T2 - Berliner Polymerentage 2000 CY - Berlin, Germany DA - 2000-10-09 PY - 2000 AN - OPUS4-11134 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Krüger, Ralph-Peter A1 - Just, Ulrich A1 - Wittke, Wolfgang T1 - LC-MALDI Coupling for "quantitative" Analysis of Polymers T2 - NIST CY - Gaithersburg, MD, USA DA - 2002-11-06 PY - 2002 AN - OPUS4-11138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Knop, K. A1 - Thünemann, Andreas T1 - Structure and end-group analysis of complex hexanediol-neopentylglycol-adipic acid copolyesters by matrix-assisted laser desorption/ionization collision-induced dissociation tandem mass spectrometry N2 - Sequences and end groups of complex copolyesters were determined by fragmentation analysis by means of matrix-assisted laser desorption/ionization collision-induced dissociation tandem mass spectrometry (MALDI CID MS/MS). The complexity of the crude copolyester mixture was reduced by a chromatographic separation followed by a MALDI time-of-flight (TOF) investigation of fractions. Due to overlapping compositional and end-group information a clear assignment of end groups was very difficult. However, the fragmentation of suitable precursor ions resulted in typical fragment ion patterns and, therefore, enabled a fast and unambiguous determination of the end groups and composition of this important class of polymers. KW - Fragmentierung KW - MALDI Massenspektrometrie KW - Polymere KW - MS/MS PY - 2009 DO - https://doi.org/10.1002/rcm.4191 SN - 0951-4198 SN - 1097-0231 VL - 23 IS - 17 SP - 2768 EP - 2774 PB - Wiley CY - Chichester AN - OPUS4-20929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fandrich, Nick A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Pfeifer, Dietmar A1 - Staal, B. A1 - Thünemann, Andreas A1 - Laschewsky, A. T1 - Characterization of new amphiphilic block copolymers of N-vinyl pyrrolidone and vinyl acetate, 1 - analysis of copolymer composition, end groups, molar masses and molar mass distributions N2 - New amphiphilic block copolymers consisting of N-vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4-dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. 13C NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, 13C NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non-ideal RAFT mechanism. KW - Amphiphiles KW - Block copolymers KW - Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) KW - N-vinyl pyrrolidone KW - Reversible addition/fragmentation chain transfer (RAFT) PY - 2010 DO - https://doi.org/10.1002/macp.200900466 SN - 1022-1352 SN - 1521-3935 VL - 211 IS - 8 SP - 869 EP - 878 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-21905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gruendling, T. A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Barner-Kowollik, C. T1 - Mass spectrometry in polymer chemistry: a state-of-the-art up-date N2 - Two decades after the introduction of matrix assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI), soft ionization mass spectrometry represents a powerful toolset for the structural investigation of synthetic polymers. The present review highlights the current state-of-the-art, covering the latest developments of novel techniques, enabling instrumentation as well as the important applications of soft ionization MS from the beginning of 2008. Special attention is paid to the role that soft ionization MS has played in the mechanistic investigation of radical polymerization processes since 2005. KW - Polymerization mechanisms KW - Mass spectrometry KW - LC-MS coupling PY - 2010 DO - https://doi.org/10.1039/b9py00347a SN - 1759-9954 SN - 1759-9962 VL - 1 IS - 5 SP - 599 EP - 617 AN - OPUS4-21906 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana T1 - MALDI Imaging MS von Polymeren T2 - BRUKER-Anwendertreffen CY - Kassel, Germany DA - 2011-03-21 PY - 2011 AN - OPUS4-23603 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero A1 - Sturm, Heinz A1 - Weidner, Steffen T1 - Breaking polymer chains by dynamic plowing lithography N2 - The adhesion of poly(methyl methacrylate) (PMMA) and polystyrene (PS) films, whose surface has been previously structured by dynamic plowing lithography (DPL), has been measured by means of force–displacement curves. The different adhesion of modified and unmodified PS leads to the assumption that polymer chains are broken during DPL. After measuring the energy dissipated by the tip during DPL, in order to check that the transferred energy is sufficient to break covalent bonds, the polymer chain scission caused by the lithographic process has been definitely confirmed by size exclusion chromatography measurements of the lithographed films. KW - AFM KW - Nanolithography KW - Chain scission PY - 2002 DO - https://doi.org/10.1016/S0032-3861(02)00285-9 SN - 0032-3861 SN - 1873-2291 VL - 43 IS - 16 SP - 4461 EP - 4466 PB - Springer CY - Berlin AN - OPUS4-1608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Sturm, Heinz A1 - Vogel, Lydia T1 - Untersuchung von plasmamodifizierten Polymeren mit speziellen Analysenmethoden T2 - Abteilungsseminar, BAM, Abt. VI CY - Berlin, Germany DA - 1996-05-02 PY - 1996 AN - OPUS4-6411 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -