A variable constraint tube model for size effects of polymer nano-structures

作者:Tang Shan*; Greene M Steven; Liu Wing Kam
来源:Applied Physics Letters, 2011, 99(19): 191910.
DOI:10.1063/1.3660585

摘要

We develop a molecular-based hyperelastic model to simulate the size dependent mechanical properties of polymer nano- structures. We assume that polymer chains are confined to a different "tube" size in a boundary layer than that in the core, which alters the free energy and produces the size effect. Simulations also explore anisotropic orientations of polymer chains and surface tension. The axial modulus of nanofibers is studied in detail, although the model is applicable to other systems like thin films and nano- biological systems.