Strain energy density based effective potential for polymer grafted spherical nanoparticles

Polymer-grafted nanoparticles (PGN) form single-component nanocomposites that have gained significant popularity as they allow for superior control over ordering and mechanical properties. However, the design space for PGNs is huge and it is challenging to find optimal molecular parameters that yield a particular mechanical outcome. To overcome this issue, we have developed a strategy to convert the strain energy density obtained from coarse-grained molecular dynamics (CG-MD) simulations to the form of an effective interparticle potential. The double exponential potential can capture the interaction between spherical nanoparticles and circumvent the need to explicitly model grafted chains. Upscaling to a single particle representation increases the computation speed by approximately four orders of magnitude relative to coarse-grained models and enables us to investigate the design space (consisting of polymer chain length, grafting density, nanoparticle radius) with less computational cost and without losing the underlying physics. This novel framework is foundational for micron-scale modeling of single and multi-component polymer-grafted nanoparticle composite films under mechanical loads, including microballistic impact.