(362a) Atomistic/Molecular Scale Integration of Polymer/Solid Surface Interaction Models

The physiochemical properties of oligomeric/polymeric materials are controlled by molecular level architecture, and the many polymer internal degrees of freedom span a range of time/length scales requiring an integrated multiscale description.[1] Many engineering applications involve polymeric fluids interacting with solid surfaces adding to the complexity of the theoretical description.[2]   Typical applications in areas such as energy, tribology, and catalysis must meet the challenge of accurately and efficiently designing polymer melt/solid surface materials where performance is governed by multi-physical/multiscale phenomena.  

A natural modeling path towards linking disparate scales in two-phase material design is a bottom-to-top approach.  The essence of this multiscale integration approach is in constructing models with varying degrees of resolution while passing only the most relevant physical information from high resolution, highly complex models to lower resolution descriptions containing much less detail.  This reduction in the degrees of freedom facilitates efficient computation of models approaching the macroscopic device scale for the purpose of technological advancement.   

We utilize atomistic/ molecular scale modeling and integration techniques in modeling polymers with varied molecular architecture including linear di-block and random copolymers as well as   branched/starlike polymers on a variety of solid surfaces. Case studies dealing with perfluorinated polymer nano films coating various allotropes of carbon are examined to illustrate our hierarchal multiscale approach.  The bottom-level descriptions are established utilizing ab initio method based models of polymer-polymer and polymer-surface interactions and are linked with lower resolution molecular descriptions via coarse-graining procedures.  The atomistic scale interactions are incorporated into coarse-grained molecular dynamics simulations of the polymer/solid surface system to quantify static and dynamic physiochemical properties.  Thus, a correlation between atomistic/molecular architecture and macroscopic/mesoscale material performance is established.     

1. P. S. Chung, M. S. Jhon, and L. T. Biegler, “Chapter 2- The Holistic Strategy in Multi-Scale Modeling”, Advances in Chemical Engineering,Ed. G. B. Martin, New York: Academic Press 2011, 59-118.

2. P. S. Chung, R. Smith, S. H. Vemuri, Y. I. Jhon, K. Tak, I. Moon, L. T. Biegler, and M. S. Jhon, “Multi-scale/mult-physical modeling in head/disk interface of magnetic data storage,” J. Appl. Phys.  111, 07B712 (2012).