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 -