Mesoscale Simulations of Polymer Solution Self-Assembly: Selection of Model Parameters within an Implicit Solvent Approximation.

Juhae Park,Abelardo Ramírez-Hernández,Su-Mi Hur,Vikram Thapar

doi:10.3390/polym13060953

Juhae Park, Abelardo Ramírez-Hernández + Show 2 more

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https://doi.org/10.3390/polym13060953

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Abstract

Coarse-grained modeling is an outcome of scientific endeavors to address the broad spectrum of time and length scales encountered in polymer systems. However, providing a faithful structural and dynamic characterization/description is challenging for several reasons, particularly in the selection of appropriate model parameters. By using a hybrid particle- and field-based approach with a generalized energy functional expressed in terms of density fields, we explore model parameter spaces over a broad range and map the relation between parameter values with experimentally measurable quantities, such as single-chain scaling exponent, chain density, and interfacial and surface tension. The obtained parameter map allows us to successfully reproduce experimentally observed polymer solution assembly over a wide range of concentrations and solvent qualities. The approach is further applied to simulate structure and shape evolution in emulsified block copolymer droplets where concentration and domain shape change continuously during the process.

Highlights

Self-assembly of polymer systems has been a topic of considerable attention in recent decades due to its relevance to many advanced nanotechnologies, such as drug delivery [1,2], medical imaging [3], nanoelectronics [4], and phononic or photonic devices [5,6,7].extensive theoretical and numerical studies have been undertaken to understand the underlying physical principles [8,9,10,11,12]
We present our efforts to expand the capability of an implicit solvent virial model by obtaining correlations between model parameters and experimentally measurable quantities, such as single-chain scaling exponent, average chain density, and interfacial and surface tensions
While Monte Carlo (MC) simulations are applied in conjunction with both grid-based and grid-less approaches, MD simulations are only used with grid-less approaches as the required estimation of forces is more straightforward

Summary

Introduction

Self-assembly of polymer systems has been a topic of considerable attention in recent decades due to its relevance to many advanced nanotechnologies, such as drug delivery [1,2], medical imaging [3], nanoelectronics [4], and phononic or photonic devices [5,6,7].extensive theoretical and numerical studies have been undertaken to understand the underlying physical principles [8,9,10,11,12]. A range of coarse-grained models in which atoms are lumped together into coarse-grained segments has been developed [8,12,13,14]. One such class of models is bottom-up models that are specific to systems of interest and attempt to retain as much detail as possible about the polymers under study; these models involve conducting parameterization studies to derive effective potentials by encoding information obtained from atomistic simulations [8,9,14,15]. Physicsbased key interactions represented either through particle- or field-based approaches have successfully been applied to describe how changes in enthalpic and entropic contributions affect structure formation [8,11,16]

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