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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 41: Nanoparticles and Composite Materials
CPP 41.5: Vortrag
Donnerstag, 3. April 2014, 10:30–10:45, ZEU 222
Tracer Diffusion Studies of Tailored Nanostructured Composites — •Andy Kiessling1, Vincent Le Houérou2, Christian Gauthier2, and Eckhard Bartsch1 — 1Department of Physical Chemistry, Albertstr. 21, 79104 Freiburg, Germany — 2Institut Charles Sadron - CNRS UPR 022, 23 rue du Loess - BP 84047, 67034 Strasbourg cedex 2, France
Volatile organic compounds in solvent cast film formation act as softener and leave behind films of high material strength after evaporation. Water-based systems lack this ability, but this drawback can be circumvented by the combination of components with complementary properties like high Tg core - low Tg shell polymer dispersions. The improved properties of coatings from water-based core-shell polymer dispersions like enhanced scratch resistance are attributed to a layer of restricted mobility of the polymer surrounding the high Tg cores. Studies addressing the molecular origin of the observed macroscopic enhancements are scarce. Applying a tracer diffusion method (Forced Rayleigh Scattering) allows an analysis of the nanostructured composites on a molecular level on different length scales. Through the superposition of two laser beams, a holographic grating is created. The diffusion of the dye is detectable as time decay of an optical Bragg scattering signal. Interpretation and modeling of the signal provide information about the mobility of the tracer in various film compartments, which is characterized by diffusion coefficients and diffusion lengths. These investigations are complemented by studies on the macroscopic film properties, notably the behavior when submitted to sliding contact.