Experimental evidence for a new parameter to control the glass transition of confined polymers.
Polymer nanocomposites can be used to study confinement effects on the polymer glass transition temperature (Tg) in a controlled manner by varying interparticle spacing. Using gold nanoparticles in polymethylmethacrylate, we show how the polymer Tg can be tuned by variation of the nanoparticle-polymer interface width (sigma), keeping interparticle spacing fixed. We report the first experimental observation of a crossover in the sign of Tg deviation for confined polymers by variation of sigma and propose a model to explain the dependence of crossover width on the spatial extent of cooperatively rearranging regions.
Srivastava
S
S
Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
Basu
J K
JK