TY - JOUR A1 - Cappella, Brunero A1 - Sturm, Heinz A1 - Weidner, Steffen T1 - Breaking polymer chains by dynamic plowing lithography JF - Polymer 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 - JOUR A1 - Cappella, Brunero A1 - Sturm, Heinz A1 - Schulz, Eckhard T1 - Stiffness and adhesion characterization of nanolithographed poly(methyl methacrylate) by means of force-displacement curves JF - Journal of adhesion science and technology N2 - Poly(methyl methacrylate) (PMMA) surfaces have been modified by dynamic plowing lithography. The resulting modified structures, presenting regions of different densities and stiffnesses, have been studied by force–displacement curves. The elasto-plastic response, the stiffness, and the adhesion of the modified samples have been characterized. Force–displacement curves are able to distinguish between unmodified PMMA and two different structures resulting from the lithography, i.e. compressed PMMA and low density PMMA. In particular, the low density regions are made up of cluster-like globular particles, whose elasto-plastic response and adhesion are measured and whose contribution to the total elasto-plastic response and to the adhesion has been studied in detail. KW - AFM KW - Lithography KW - Force-displacement curves KW - Stiffness KW - Adhesion KW - Elasto-plastic response PY - 2002 DO - https://doi.org/10.1163/156856102760136472 SN - 0169-4243 SN - 1568-5616 VL - 16 IS - 7 SP - 921 EP - 933 PB - VNU Science Press CY - Utrecht AN - OPUS4-1609 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero A1 - Kaliappan, Senthil Kumar A1 - Sturm, Heinz T1 - Using AFM Force-Distance Curves To Study the Glass-to-Rubber Transition of Amorphous Polymers and Their Elastic-Plastic Properties as a Function of Temperature JF - Macromolecules N2 - Force-displacement curves have been obtained with a commercial atomic force microscope (AFM) at different temperatures and probe rates on a thick film of poly(n-butyl methacrylate) (PnBMA). The analysis of the force-displacement curves has been focused on the contact portion of the curves, giving information about the stiffness of the sample and its Young's modulus. A novel model of sample deformations that extends the basic equations of the elastic continuum contact theories to the plastic deformations is presented. This model gives several insights into the processes of deformation of soft samples and permits to calculate not only the parameters of the Williams-Landel-Ferry equation but also the Young's modulus and the yielding force of the polymer as a function of temperature and/or probe rate. These quantities have been measured in a wide range of temperatures (70 K) and probe rates (6 decades) for the first time with the AFM, and the results are in very good agreement with measurements performed with customary techniques, such as broadband spectroscopy and dynamic mechanical analysis. KW - AFM KW - Polymers KW - Glas transition temperature PY - 2005 DO - https://doi.org/10.1021/ma040135f SN - 0024-9297 SN - 1520-5835 VL - 38 SP - 1874 EP - 1881 PB - American Chemical Society CY - Washington, DC AN - OPUS4-7274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silbernagl, Dorothee A1 - Sturm, Heinz A1 - Cappella, Brunero T1 - Influence of film-substrate adhesion on the mechanical properties of thin polymer films JF - Langmuir KW - Adhesion KW - AFM KW - Thin film KW - Mechanical properties KW - Force-distance curves PY - 2009 DO - https://doi.org/10.1021/la8041007 SN - 0743-7463 SN - 1520-5827 VL - 25 IS - 9 SP - 5091 EP - 5097 PB - American Chemical Society CY - Washington, DC AN - OPUS4-19363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -