A coupled MD-FE methodology to characterize mechanical interphases in polymeric nanocomposites

This contribution introduces an unconventional procedure to characterize spatial profiles of elastic and inelastic properties inside polymer interphases around nanoparticles. Interphases denote those regions in the matrix whose mechanical are influenced by filler surfaces thus deviate from bulk properties. They particular relevance case nano-sized particles with a comparatively large surface-to-volume ratio hence can explain frequent observation that overall nanocomposites cannot be determined classical mixing rules, which only consider behavior individual constituents. Interphase characterization for poses hardly solvable challenges experimenter is still unsolved problem many cases. Instead real experiments, we perform pseudo experiments using our recently developed Capriccio method, MD-FE domain-decomposition tool specifically designed amorphous polymers. These pseudo-experimental data then serve as input typical inverse parameter identification. With this procedure, spatially varying are, first time, translated into intuitively understandable continuum parameters. As model material, employ silica-enforced polystyrene, reveals exponential saturation Young’s modulus yield stress interphase, where former takes about seven times value at particle surface latter roughly triples. Interestingly, hardening coefficient Poisson’s remain nearly constant interphase. Besides gaining insight constitutive influence particles, these unexpected intriguing results also offer interesting explanatory options failure nanocomposites.