Coarse-grained MD Simulations for Adhesive Polymer Networks Interlocking with Patterned-Surface

Adhesion between inorganic substrates and polymeric materials such as crosslinked rubber and epoxy resin is of interest from both fundamental science and engineering applications. Advances in processing techniques, crosslinking control techniques, and measurement techniques are enabling experiments on the nanometer to sub-micrometer scale, where the size of the crosslinked network is strongly correlated with the size of the surface pattern/shape of the substrates. For molecular dynamics (MD) simulations, there is a strong demand for automatic search of characteristic behaviors from a large parameter space and suggestion of experimental conditions in advance of fabrication and mesurements. In our previous work [1], we constructed a coarse-grained MD (CGMD) model using overhanging shapes described by the River Meander Curves (parametric curves).

In the present work, we applied a much large deformetion for the system with attractive patterned substrates (r_c,wall = 2.0) at T = 0.3 < T_g ~ 0.42. We clarified that the cases with overhanging patterned shows mechnical interlocking with great increasing the fracture energy in the stress-strain curves. The mechanical interlocking increases the effective adhesive strength, leading to cohesive failure on the polymer matrix and the stretched chains are observed to form dendritic fibrils in voids.