(253am) A Transferable Multi-Resolution Coarse-Grained Model for Amorphous Silica Nanoparticles
- Conference: AIChE Annual Meeting
- Year: 2016
- Proceeding: 2016 AIChE Annual Meeting
- Group: Computational Molecular Science and Engineering Forum
- Time: Monday, November 14, 2016 - 6:00pm-8:00pm
In this work, we develop a CG model for amorphous silica nanoparticles using a potential-matching approach. Here, nanoparticles are represented as a collection of individual CG beads, modeled via a Mie potential, whose parameters are tuned such that the effective interaction of the collection of CG particles matches the interaction between atomistically detailed amorphous silica nanoparticles. To generate potentials that are transferable, CG parameters are derived to simultaneously match a range of nanoparticle sizes. Collective optimization of the parameters makes use of the constrained optimization by linear approximation (COBYLA) method provided by the openMDAO framework , resulting in CG potentials that match their atomistic counterparts with high fidelity. Higher and lower resolution models are also presented, corresponding to changes in the CG particle surface density, where such changes are made trivially using the mBuild software package . Point particle models of NPs, representing the lowest resolution of coarse-graining, are also presented. We further demonstrate the extension of this potential matching procedure to obtain cross-interactions between CG particles and alkanes, allowing alkane-grafted CG amorphous silica nanoparticles to be constructed, whose properties show close agreement with atomistic models.
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