The impact of fragility on the properties of the glass formation of polymer nanoparticle composites

ORAL

Abstract

We investigate the effects of nanoparticles on glass formation in a model polymer melt by molecular dynamics simulations. The addition of nanoparticles allows us to change the relaxation time, glass transition temperature $T_g$, the fragility of glass formation in a controlled fashion. We show that the structural relaxation for different temperatures, concentrations, and polymer-NP concentrations can be expressed in terms of a simple universal function of the short-time Debye-Waller factor. We further examine how the stretching exponent $\beta$ and the degree of the breakdown of the Stokes-Einstein relation depend upon fragility, which we relate to the extent of cooperative motion.

–

Authors

  • Beatriz A. Pazmino Betancourt

    Physics Dept., Wesleyan University, Middletown, CT

  • Jack Douglas

    Materials Science and Engineering Division, NIST, Gaithersburg, MD, NIST, Gaithersburg, MD, Polymer Division, NIST, Gaithersburg, MD, The National Institute of Standards and Technology, Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA

  • Francis Starr

    Wesleyan University, Middletown CT, Physics Dept., Wesleyan University, Middletown, CT, Department of Physics, Wesleyan University, Middletown, CT 06459, USA