PECASE: Nanoscale Confinement in Polymers: Integrated Research and Education in Nanoscale Experimental Mechanics

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

This Faculty Early Career Development (CAREER) program seeks to quantify the mechanical behavior of polymers subjected to nanoscale confinement and restricted/enhanced macromolecular mobility near hard surfaces. The latter will be designed to simulate the behavior of polymer molecules near pristine and functionalized nanotubes and nanofibers in polymer nanocomposites. The large surface-to-volume ratio in these material systems is such that the hard phase restricts molecular mobility and conformations. As a result, the entire composite may be practically an interphase, with local and effective macroscopic properties being very different from pristine bulk polymers. Experimental nanoscale probe methods will be developed to determine variations in molecular dissipation at the nanoscale and to quantify the collective time-dependent response of surface molecules in ultra-thin polymer films. Measurements of the viscoelastic creep functions and glass transition temperatures as a function of polymer layer thickness will provide the data to assess molecular conformations near hard interfaces. Due to the lack of local information on polymer matrix modification near hard surfaces, the fabrication of strong and tough multifunctional and lightweight polymeric nanocomposites is far from reaching its projected potential. If successful, this program will set the foundations for controlled and efficient design of high performance nanostructured polymers and establish property limits for multiphase polymers. The experimental results from this program will be essential material parameters for molecular dynamics and micromechanics models with applications to nanocomposites, biological systems, nanoimprinting, nanofluidic arrays, etc. The outreach plan of this CAREER award will (a) inspire high school students to study aerospace engineering via an engineering teaching kit that will increase high school student technology awareness in hierarchical materials for aerospace applications, (b) provide hands-on education on nanoscale mechanics to undergraduate and graduate students, and (c) support professionals with nanoscale mechanics laboratory training.