A simulation study on nonlinear mechanical responses of glassy polymer nanofibers

The confined polymer glasses, such as glassy polymer fibers, exhibit unique glassy behaviors that differ from bulk polymer glasses. We perform molecular dynamics simulations and study nonlinear mechanical responses of glassy polymer nanofibers under uniaxial deformation. We investigate not only nonlinear mechanical responses but also the dependence of mechanical properties on the strain rates of typical polymer glasses, which were observed experiments. We find from our simulations that the local modulus in the surface region of fibers is less than that in the core region of fibers. Also, the non-affine displacements in the surface region of glassy polymer fibers are greater than those in bulk polymer glasses. These results mean that the microscopic events during deformation are closely related to the mechanical responses of polymer glasses.