Chemie und Prozesstechnik
Filtern
Erscheinungsjahr
- 2019 (233) (entfernen)
Dokumenttyp
Sprache
- Englisch (203)
- Deutsch (29)
- Mehrsprachig (1)
Schlagworte
- Mechanochemistry (21)
- Nanoparticles (21)
- Mikroplastik (13)
- XPS (13)
- In situ (11)
- EPMA (10)
- SAXS (10)
- Synchrotron (10)
- XRD (9)
- Microplastics (7)
- Electron microscopy (6)
- Imaging (6)
- MOF (6)
- TED-GC-MS (6)
- X-ray spectroscopy (6)
- Discotic Liquid Crystals (5)
- NAP-XPS (5)
- Small-angle scattering (5)
- Standardisation (5)
- Thin films (5)
- Traceability (5)
- VAMAS (5)
- XRF (5)
- Analytik (4)
- Catalysis (4)
- Electron probe microanalysis (EPMA) (4)
- Fluorescence (4)
- Klebfestigkeit (4)
- NEXAFS (4)
- Nanocomposites (4)
- Particle size distribution (4)
- Reference materials (4)
- ToF-SIMS (4)
- X-ray (4)
- Acoustic levitation (3)
- Atomic Force Microscopy (AFM) (3)
- BAMline (3)
- Beamline (3)
- Biofilms (3)
- Broadband dielectric spectroscopy (3)
- Cement (3)
- Fe-Ni (3)
- Haftfestigkeit (3)
- LCCC (3)
- Mass spectrometry of polymers (3)
- Material characterization (3)
- Metal phosphonates (3)
- Mueller-Matrix imaging ellipsometry (3)
- PXRD (3)
- Polymers (3)
- Si-Ge (3)
- Software (3)
- Spectroscopic ellipsometry (3)
- Spectroscopy (3)
- Spectroskopic Imaging (3)
- Synthesis (3)
- Thin film analysis (3)
- Thin polymer films (3)
- Titanium dioxide (3)
- X-ray scattering (3)
- ALD-Hybridprozesse (2)
- ATR-FTIR spectroscopy (2)
- Absorption edge tomography (2)
- Al2O3-Schichten (2)
- Analysis (2)
- Analytische Zentrifuge (2)
- Asymmetrical flow field flow fractionation (AF4) (2)
- Atomic Layer Deposition (2)
- Brechungsindex (2)
- C3A (2)
- CAT-Technologie (2)
- Capillary electrophoresis (CE) (2)
- Co-crystal (2)
- Cocrystal (2)
- Coded Apertures (2)
- Coded apertures (2)
- Copolymer (2)
- Core-shell nanoparticles (2)
- Corrosion (2)
- Corrosion monitoring (2)
- DNA (2)
- DVS (2)
- Data (2)
- Delayed addition (2)
- Dosimetry (2)
- Early hydration (2)
- Electron irradiation (2)
- Electron probe microanalysis (2)
- Ellipsometrie (2)
- Ellipsometry (2)
- Epoxy (2)
- Ettringite (2)
- FTIR (2)
- FeNi (2)
- Flash DSC (2)
- Geant4 (2)
- Geant4-DNA (2)
- Glucose (2)
- HKUST-1 (2)
- Haftvermittler (2)
- ISO (2)
- Inter-laboratory comparison (2)
- Iridium-titanium mixed oxides (2)
- MIC (2)
- Mesoporous thin films (2)
- Metrology (2)
- Microanalysis (2)
- Microbeam analysis (2)
- Microdosimetry (2)
- Microstructure (2)
- Microwave synthesis (2)
- Mikroskaliert (2)
- Molecular sieves (2)
- Monte-Carlo Simulation (2)
- Multivariate data analysis (2)
- Müller-Matrix-Ellipsometrie (2)
- NanoSIMS (2)
- Nanocharacterisation (2)
- Nanomaterial (2)
- Nanomaterials (2)
- Nanoskaliert (2)
- Nanostructure (2)
- Non-spherical shape (2)
- Oberflächenenergie (2)
- Oberflächengeometrie (2)
- Polycarboxylate ether (PCE) (2)
- Pre-standardisation (2)
- Principal component analysis (PCA) (2)
- Probenahme (2)
- Reference material (2)
- SEC (2)
- SEM/EDS (2)
- Sampling (2)
- Sampling techniques (2)
- SiGe (2)
- Small angle scattering (2)
- Specific heat spectroscopy (2)
- Standarisierung (2)
- Structural anomalies (2)
- Structural inhomogenities (2)
- Surface functionalization (2)
- Synchrotron tomography (2)
- Test material (2)
- Uncertainties (2)
- Verbundfestigkeit (2)
- Water (2)
- X-ray Photoelectron Spectroscopy (XPS) (2)
- X-ray Spectroscopy (2)
- X-ray absorption fine structure (2)
- X-ray diffraction (2)
- X-ray fluorescence (2)
- XANES (2)
- Zinc oxide (2)
- µ-XRF (2)
- (ter-)pyridineterminated self-assembled monolayer (1)
- 2-oxazoline (1)
- 3D coherence scanning interferometry (CSI) (1)
- AET (1)
- Absorption (1)
- Adhäsion (1)
- Admixtures (1)
- Advanced Materials (1)
- Advanced materials (1)
- Agarose (1)
- Ageing (1)
- Alite (1)
- Alkoxysilanes (1)
- Anatase (1)
- Anomalous Small Angle X-ray Scattering (1)
- Antibacterial surface coatings (1)
- Antifouling surface coatings (1)
- Antifriction coefficient (1)
- Antimony oxychloride ( Sb4O5Cl2) (1)
- Antiviral activity (1)
- Artificial intelligence (1)
- Atomic force microscopy (1)
- Atomic fraction (1)
- Aufbereitung (1)
- Auger Electron Spectroscopy (1)
- Automation (1)
- Azobenzene (1)
- BET specific surface area (1)
- BSA (1)
- Bacteria (1)
- Ball milling (1)
- Battery (1)
- Bestimmung der Messunsicherheit (1)
- Biochip (1)
- Biocorrosion (1)
- Biofilmbildung (1)
- Biofunctional Molecules (1)
- Biosensors (1)
- Boehmite (1)
- Boehmite nanoparticles (1)
- Bone matrix (1)
- Bovine serum albumin (1)
- Brain PET tracers (1)
- Broadband dielectric microscopy (1)
- Bulk material (1)
- Böden (1)
- C-C coupling (1)
- C3S (1)
- CXC (1)
- Capillary electrophoresis (1)
- Catalysts (1)
- Catechol (1)
- Categorisation scheme (1)
- Cationic ring opening polymerization (1)
- Centrifugal Adhesion Testing (1)
- Centrifugal Adhesion Testing (CAT) (1)
- Centrifugal Force (1)
- Certified reference materials (1)
- Certified standards (1)
- Ciprofloxacin (1)
- Cleaning (1)
- Click chemistry (1)
- Cobalt and zinc oxides (1)
- Cobalt deposition (1)
- Coded aperture (1)
- Color X-ray Camera (1)
- Comparability of Measurement Results (1)
- Compressibility (1)
- Compressive Stress (1)
- Computational chemistry (1)
- Computer simulation (1)
- Conference (1)
- Controlled-shape (1)
- Coordination Polymers (1)
- Cristobalite frameworks (1)
- Crosslinking density (1)
- Crystal engineering (1)
- Crystallization (1)
- CuO nanoparticles (1)
- Curved surfaces (1)
- Cytotoxicity (1)
- DFT (1)
- DIN EN ISO/IEC 17025:2018 (1)
- DSC (1)
- Data corrections (1)
- Decision support (1)
- Deep work (1)
- Definition of nanomaterial (1)
- Detektion (1)
- Dielectric properties (1)
- Dielectric spectroscopy (1)
- Digestion (1)
- Direct/indirect photolysis (1)
- Double complex salts (1)
- Dünne Schichten (1)
- E. coli (1)
- EBSD (1)
- EC definition of a nanomaterial (1)
- EC nanomaterial definition (1)
- EDS (1)
- EDS X-ray spectrometer (1)
- EDS performance check (1)
- EMPIR (1)
- ESCA/XPS (1)
- EXAFS (1)
- Electrical conductivity (1)
- Electrochemical deposition (ECD) (1)
- Electrochemical sensing (1)
- Electrochemistry (1)
- Elemental composition (1)
- Ellipsometric porosimetry (1)
- Experimental setup (1)
- Expert system (1)
- Ferrihydrite (1)
- Fiber Bragg grating (FBG) (1)
- Field of Analysis (1)
- Fluorescence correction (1)
- Fluoride (1)
- Fourier Transform Infra Red Spectroscopy (1)
- Fully aromatic frameworks (1)
- Functionalized nanographene (1)
- Fundamentals (1)
- GUM-compliance (1)
- Gas separation membranes (1)
- Genotoxic and oxidative damage (1)
- Geology (1)
- Goethite (1)
- Graphene (1)
- Green rust (1)
- Grouping (1)
- Guest uptake/release (1)
- H-terminated Si3N4 films (1)
- HRMS (1)
- Hamonisierung (1)
- Harmonisation (1)
- Harmonisierung (1)
- Hazardous substances (1)
- High repetition-rate (1)
- High specific surface area (1)
- High-resolution synchrotron XRF (1)
- High-throughput screening (1)
- Histology (1)
- Human umbilical cell adhesion (1)
- Hydrogen generation (1)
- Hydrogen photoproduction (1)
- Hydrophilic interaction chromatography (1)
- Hydrothermal synthesis (1)
- Härte (1)
- IIT (1)
- ISO 14577 (1)
- Iinter-laboratory comparison (1)
- Imidazole (1)
- Impact diamonds (1)
- Implant material (1)
- Infrared nano AFM (1)
- Inlet ionization (1)
- Instrumented Indentation Testing (1)
- Instrumentierte Eindringprüfung (1)
- Instrumentierte Eindringprüfung (IIT) (1)
- Intermodulation (1)
- Intermodulation AFM (1)
- International Meter Convention (1)
- Interphase (1)
- Introduction (1)
- Iodine (1)
- Ion mobility (1)
- Ionic liquid (1)
- Iridium oxide (1)
- Klassifizierung (1)
- Kleb- und Haftfestigkeit (1)
- Knoevenagel condensation (1)
- Kompaktierbarkeit (1)
- Kompressibilität (1)
- LC / MALDI-TOF-MS coupling (1)
- LC x ESI-TOF-MS (1)
- LC x MALDI/ESI-TOF-MS (1)
- LC x MALDI/ESI-TOF-MS coupling (1)
- LC-MS (1)
- Laterally-resolved (1)
- Layer-by-layer deposition (1)
- Levitation (1)
- Linear polyglycerol (1)
- Liquid chromatography of polymers (1)
- Liquids (1)
- Localised corrosion (1)
- Lonsdaleite (1)
- MALDI Imaging (1)
- MALDI-TOF Massenspektrometrie (1)
- Machine learning (1)
- Maia detector (1)
- Marble sculptures (1)
- Mass spectrometry (1)
- Materials (1)
- Matrices (1)
- Mechanical Flexiblity (1)
- Mechanochemie (1)
- Mehr-Proben-Prüfverfahren (1)
- Mehrprobenprüfung (1)
- Mesoporous films (1)
- Mesoporous iridium-titanium mixed oxides (1)
- Mesoporous mixed metal oxide films (1)
- Messtechnik (1)
- Messunsicherheit (1)
- Metal carbides (1)
- Metal organic frameworks (1)
- Metal-organic-frameworks (1)
- Metal– organic frameworks (1)
- Metal–organic frameworks (1)
- Micellar chromatography (1)
- Microencapsulation (1)
- Microplastic (1)
- Microwave (1)
- Milling (1)
- Mineral tranformation (1)
- Modelling (1)
- Molecular mobility (1)
- Monte Carlo (1)
- Monte-Carlo Simulations (1)
- Mueller-Matrix Ellipsometry (1)
- Multivariate Analyse (1)
- Mussel-inspired adhesives (1)
- Mussel-inspired dendritic polyglycerol (MI-dPG) (1)
- NIR spectroscopy (1)
- NMR spectroscopy (1)
- Nanocasting (1)
- Nanoconfinement (1)
- Nanomaterial Properties (1)
- Nanomaterialien (1)
- Nanomechanical properties (1)
- Nanometrology (1)
- Nanoparticle (1)
- Nanoparticle Characterization (1)
- Nanoparticles with same nominal diameter (1)
- Nanoparticles with same nominal diameter; surface coating; two-dimensional off-line coupling (1)
- Nanoporous (1)
- Nanorods (1)
- Nanoscale (1)
- Nanosheets (1)
- Nanostructure quantification (1)
- Nanostructured material (1)
- Near edge X-ray absorption fine structure (1)
- Near-ambient pressure (1)
- Neuartige Materialien (1)
- Neural network (1)
- Neutron Scattering (1)
- Niedrigenergie-Polymeren (1)
- Nitrene[2+1]cycloaddition (1)
- Non-spherical (1)
- Nonporous SiO2 (1)
- Normung (1)
- Oberflächenanalytik (1)
- Oberflächenmesstechnik (1)
- Oberflächentechnik (1)
- Optical fibers (1)
- Optical properties (1)
- Optimierung (1)
- Ordered mesoporous silica (1)
- Organic compounds (1)
- Outreach (1)
- Oxidation (1)
- Oxocobaltates (1)
- Oxygen Evolution Catalyst (1)
- Oxygen evolution reaction (1)
- Oxygen evolution reaction (OER) (1)
- Oxygen reduction reaction (1)
- P25 (1)
- PC characterisation (1)
- Pair Distribution Functions (1)
- Performance check (1)
- Phenolic acid (1)
- Phosphinine (1)
- Phosphonates (1)
- Phosphorus (1)
- Photo-transformation products (1)
- Photochromism (1)
- Photooxidation (1)
- Photoswitchable monolayers (1)
- Physical and chemical processes (1)
- Plasma (1)
- Platinum (1)
- Polarization spectroscopy (1)
- Pollenkörner (1)
- Polyethylene glycol (1)
- Polyethylene glycol (PEG)-grafting antifouling surface (1)
- Polymer (1)
- Polymer of intrinsic microporosity (1)
- Polymers of Intrinsic Microporosity (1)
- Polymorphism (1)
- Polyoxocation (1)
- Pomodore (1)
- Pore size tailoring (1)
- Porosity (1)
- Porous layers (1)
- Positron emission tomography (1)
- Post-modification by L-cysteine (1)
- Powder X-ray diffraction (1)
- Practical aspects (1)
- Preparation (1)
- Probennahme (1)
- Proton cunductor (1)
- Prüftechnik (1)
- Purine P2Y1 receptors (1)
- Qualitätssicherung (1)
- Quantitative XPS (1)
- Radiation damage (1)
- Radiometabolites (1)
- Raman Spectroscopy (1)
- Raman spectroscopy (1)
- Reconstructed ion chromatograms (1)
- Reconstruction (1)
- Reference Nanomaterials (1)
- Referenzmaterialien (1)
- Regulation (1)
- Regulatory identification of nanomaterials (1)
- Regulatory risk assesment (1)
- Reifenabrieb (1)
- Rietveld (1)
- Ringversuch (1)
- Risk assessment (1)
- SEM/EDS/STRATAGem (1)
- SIMS (1)
- Salicylic acid (1)
- Salts (1)
- Scattering (1)
- Scientific communication (1)
- Scientific method (1)
- Scientific rigour (1)
- Secondary fluorescence (1)
- Secondary fluorescence correction (1)
- Sedimentationskasten (1)
- Sedimenttaionskasten (1)
- Selected Area XPS (1)
- Self-lubricating coating (1)
- Sensing (1)
- Shape-engineered (1)
- Silane (1)
- Silicon (1)
- Silver nanoparticles (1)
- Single-source precursors (1)
- Size distribution (1)
- Slags (1)
- Small Area XPS (1)
- Small Spot XPS (1)
- Sol-gel processes (1)
- Sonochemical synthesis (1)
- Specific Adsorption of N-2 and Kr (1)
- Spectroelectrochemical Techniques (1)
- Spectrometer check (1)
- Spectroscopic Imaging (1)
- Spektrale Ellipsometrie (SE) (1)
- Spontaneous emulsification (1)
- Sportböden (1)
- SsNMR (1)
- Stability (1)
- Stand der Normung (1)
- Standardization (1)
- Standardization of Ellipsometry (1)
- Streptavidin binding (1)
- Structure analysis (1)
- Structure solution (1)
- Structures under extreme conditions (1)
- Struvite (1)
- Sulfidation (1)
- Surface (1)
- Surface Chemistry (1)
- Surface Enhanced Raman Spectroscopy (1)
- Surface analyses (1)
- Surface analytic (1)
- Surface characterization (1)
- Surface chemical analysis (1)
- Surface coating (1)
- Surface modification (1)
- Surface species (1)
- Sustainability (1)
- Suzuki-Miyaura coupling (1)
- Synchroton x-ray diffraction (1)
- Synchrotron based methods (1)
- T-SEM (1)
- TTBP-TAZ (1)
- TXRF (1)
- Tattoo inks (1)
- Tensile Stress (1)
- Thermal extraction-desorption gas chromatography mass spectrometry (1)
- Thermoanalyse (1)
- Thermogravimetry (1)
- TiO2 (1)
- Time-resolved (1)
- Tire particles (1)
- Titanium Dioxide (1)
- Topometry (1)
- Topotactic phase transitions (1)
- Total scattering analysis (1)
- Toxic metals (1)
- Toxicology (1)
- Transformation pathways (1)
- Transmission function (1)
- Trinkwasser (1)
- Two-dimensional hexagonal boron nitride(h-BN) (1)
- Two-dimensional off-line coupling (1)
- Ultrasound (1)
- Umwelt (1)
- Uncertainty budgets (1)
- Underwater LIBS (1)
- Vacuum ionization (1)
- Visible light (1)
- Wastewater (1)
- Weißlichtinterferenzmikroskopie (WLIM, 3D) (1)
- White light interference microscopy(WLIM) (1)
- Women in STEM (1)
- X-ray Absorption Spectroscopy (1)
- X-ray Photoelectron Spectroscopy (1)
- X-ray absorption Fine Spectroscopy (1)
- X-ray absorption spectroscopy (1)
- X-ray and electron diffraction (1)
- X-ray detectors (1)
- X-ray photoelectron spectroscopy (1)
- X-ray spectrometry (1)
- XAFS (1)
- XAS (1)
- XPS background analysis (1)
- Zeolitic Imidazolate Frameworks (1)
- Zinc (1)
- Zinc analysis (1)
- Zinc oxide nanoparticles (1)
- digestion (1)
- mechanical properties (1)
- microplastics, sampling, sampling techniques, water (1)
- nanoindentation (1)
- nanoparticles (1)
- performance test (1)
- product specification (1)
- shape control (1)
- uncertainty (1)
- µJ-DPSS laser (1)
Organisationseinheit der BAM
- 6 Materialchemie (233) (entfernen)
Eingeladener Vortrag
- nein (97)
Ultra-SAXS can enhance the capabilities of existing SAXS/WAXS beamlines and laboratory instruments. A compact Ultra-SAXS module has been developed, which extends the measurable q-range with 0:0015 < q 1/nm) < 0:2, allowing structural dimensions between 30 < D(nm) < 4000 to be probed in addition to the range covered by a high-end SAXS/WAXS instrument. By shifting the module components in and out on their respective motor stages, SAXS/WAXS measurements can be easily and rapidly interleaved with USAXS measurements.
Im Fokus des Vorhabens steht das mit dem Innovationspreis Berlin-Brandenburg 2012 ausgezeichnete Mehr-Proben-Prüfverfahren zur Festigkeitsprüfung unter Verwendung einer analytischen Zentrifuge mit dem Ziel des Einsatzes in der Qualitätssicherung. Nachdem im MNPQ-Projekt QUO VADIS die grundsätzliche Anwendbarkeit der Zentrifugentechnologie auf Beanspruchungen auf Zug (Kleb-, Haft- und Verbundfestigkeit) nachgewiesen worden war, wurden im Vorhaben QUO VADIS PLUS folgende erweiterte Prüfszenarien und technische Weiterentwicklungen etabliert: 1. Beanspruchung auf Druck (Härte von Materialien, Kompressibilität von Schäumen, Kompaktierbarkeit von Pulvern), 2. Erweiterung der Beanspruchung auf Zug (Kombination von Normal- und Lateralkräften), 3. Erweiterung auf die Bewertung plasto-elastischenn Materialverhaltens, 4. Vermeidung von Schockwellen im Hochlastbereich
CCQM key comparison K-153 Measurement of Specific Adsorption A [mol/kg] of N-2 and Kr on nonporous SiO2 at LN temperature (to enable a traceable determination of the Specific Surface Area (BET) following ISO 9277) has been performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The objective of this key comparison is to compare the equivalency of the National Metrology Institutes (NMIs) and Designated Institutes (DIs) for the measurement of specific adsorption, BET specific surface area) of nonporous substances (sorbents, ceramics, catalytic agents, etc) used in advanced technology.
In this key comparison, a commercial nonporous silicon dioxide was supplied as a sample. Eight NMIs participated in this key comparison, but only five NMI's have reported in time. All participants used a gas adsorption method, here nitrogen and (or) krypton adsorption at 77.3 K, for analysis according to the international standards ISO 15901-2 and 9277.
In this key comparison, the degrees of equivalence uncertainties for specific adsorption nitrogen and krypton, BET specific surface area were established.
Biofouling constitutes a major challenge in the application of biosensors and biomedical implants, as well as for (food) packaging and marine equipment. In this work, an antifouling surface coating based on the combination of mussel-inspired dendritic polyglycerol (MI-dPG) and an amine-functionalized block copolymer of linear polyglycerol (lPG−b−OA11, OA = oligo-amine) was developed. The coating was compared to a MI-dPG surface which was postfunctionalized with commercially available amine-terminated Polyethylene glycol (HO−PEG−NH2) of similar molecular weight. In the current work, These coatings were compared in their chemical stability, protein fouling characteristics, and cell fouling characteristics. The lPG−b−OA11-functionalized coating showed high chemical stability in both phosphate buffered saline (PBS) and sodium dodecyl sulfate (SDS) solutions and reduced the adhesion of fibrinogen from human plasma with 99% and the adhesion of human serum albumin with 96%, in comparison to the bare titanium dioxide substrate. Furthermore, the Proliferation of human umbilical vein endothelial cells (HUVECs) was reduced with 85% when the lPG−b−OA11 system was compared to bare titanium dioxide. Additionally, a reduction of 94% was observed when the lPG−b−OA11 system was compared to tissue culture polystyrene.
The performance of functional coatings and adhesively joined hybrid components relies strongly on the stability of the polymer-metal interface. With the increasing utilization of multi-material structures in the automotive and aerospace industry, it is of great scientific and technical interest to understand the processes leading to interface degradation and to develop novel strategies to increase corrosion and delamination resistance.
The aim of this project is to develop thin epoxy-based films and their carbon nanofiller loaded composites on aluminium alloy AA2024-T3 as a model system and to investigate their interfacial stability under corrosive and coupled corrosive-mechanical load. Spin coating was used for the layer-by-layer deposition of poly[(o-cresyl glycidyl ether)-co-formaldehyde] and poly-(ethylenimine) bi-layers. Atomic force microscopy (AFM) results indicate a very homogeneous and dense film with low surface roughness. Carbon nanofillers were introduced either by mixing into the coating components or in between individual layers to control the separation between the carbon nanofillers and alloy surface. The film chemistry and barrier properties were characterized by means of spectroscopic and electrochemical methods, respectively. The degradation and delamination behavior of the epoxy-based films was characterized by means of in situ AFM corrosion experiments. The quantitative imaging (QI) mode allowed the observation of hydrogen-generation induced blister formation during exposure to corrosive electrolyte and how the local corrosion processes evolved with exposure time. Complementary energy dispersive X-ray spectroscopy (EDX) analysis was performed to correlate the corrosion behavior with the different intermetallic particle chemistries and distributions. The presentation will summarize our results on the effect of interface chemistry and carbon nanofiller – alloy separation on the initiation of local corrosion processes on thin film covered AA2024-T3 aluminium alloys.
The presentation summarizes our recent results on the coupled electrochemical methods for high resolution corrosion studies. The combination of Scanning Electrochemical Microscopy (SECM) and multielectrode (MMA) based real-time corrosion monitoring was presented as a new method for achieving high time resolution in local electrochemical analysis. Correlative imaging by means of Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) was demonstrated as a tool for the investigation of local corrosion processes initiated by the intermetallic particles (IMPs) on AA2024-T3 aluminium alloy.
The preparation of new active pharmaceutical ingredient (API) multicomponent Crystal forms, especially co-crystals and salts, is being considered as a reliable strategy to improve API solubility and bioavailability. In this study, three novel imidazole-based salts of the poorly water-soluble salicylic acid (SA) are reported exhibiting a remarkable improvement in solubility and dissolution rate properties. All structures were solved by powder X-ray diffraction. Multiple complementary techniques were used to solve co-crystal/salt ambiguities: density functional Theory calculations, Raman and 1H/13C solid-state NMR spectroscopies. In all molecular salts, the Crystal packing interactions are based on a common charged assisted +N-H SA)...O-(co-former) hydrogen bond interaction. The presence of an extra methyl group in different positions of the co-former, induced different supramolecular arrangements, yielding salts with different physicochemical properties.
All salts present much higher solubility and dissolution rate than pure SA. The most promising results were obtained for the salts with imidazole and 1-methylimidazole co-formers.
Mechanochemistry has become a valuable method for the synthesis of new materials and molecules, with a particular strength for screening and preparing multicomponent crystals. In this work, two novel cocrystals of pyrazinamide (PZA) with pimelic acid (PA) were prepared mechanochemically. Their formation was monitored in real time by in situ synchrotron powder X-ray diffraction. Control over the polymorphic form was obtained through the selective choice of liquid additive via liquid assisted grinding. Slurry experiments and dispersion-corrected density functional theory calculations suggest that Form I is the thermodynamically stable form under ambient conditions. Upon aging, Form II converts to Form I. The stability of Form II upon aging was found to depend strongly on the milling duration, intensity, and material of the milling vessels. Longer or higher energy milling drastically increased the lifetime of the Form II product. For the first time, this work also demonstrates that the choice of milling jar can have a decisive effect on the aging stability of a bulk polymorphic powder. In contrast to material prepared in steel milling vessels, the preparation of Form II in Perspex (PMMA) vessels increased its lifetime 3-fold. These findings offer a new dimension to garnering control over mechanochemical cocrystallization and demonstrate the critical importance of the careful and timely ex situ screening of ball mill grinding reactions. This will be of importance for potential industrial applications of mechanochemical cocrystallization where understanding polymorph longevity is crucial for the development of a robust preparative protocol.
For the vast majority of ellipsometric measurements, the application of planar substrates is mandatory and requires a proper sample alignment prior to the measurement. Here, the authors present a generalized approach of how to extract the isotropic ellipsometric sample parameters from an imaging Mueller-matrix measurement even if the sample is significantly misaligned. They validate the method by layer-thickness calculations based on imaging Mueller-matrix measurements of flat crystalline silicon samples that were misaligned on purpose. Furthermore, they also exploit this method’s capabilities to perform spatially resolved layer-thickness measurements of a single-layer indium-tin-oxide coating on a fused-silica microlens without the need of realignment or repositioning of the sample during the measurement.