Predicting surfactant phase behavior with a molecularly informed field theory

Kevin Shen; My Nguyen; Nicholas Sherck; Brian Yoo; Stephan Köhler; Joshua Speros; Kris T Delaney; M Scott Shell; Glenn H Fredrickson

doi:10.1016/j.jcis.2023.01.015

Predicting surfactant phase behavior with a molecularly informed field theory

J Colloid Interface Sci. 2023 May 15:638:84-98. doi: 10.1016/j.jcis.2023.01.015. Epub 2023 Jan 7.

Authors

Kevin Shen¹, My Nguyen², Nicholas Sherck², Brian Yoo³, Stephan Köhler⁴, Joshua Speros⁵, Kris T Delaney⁶, M Scott Shell⁷, Glenn H Fredrickson⁸

Affiliations

¹ Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara 93106, CA, United States; Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara 93106, CA, United States. Electronic address: kevinshen@ucsb.edu.
² Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara 93106, CA, United States.
³ BASF Corporation, Tarrytown 10591, NY, United States.
⁴ BASF SE, Ludwigshafen am Rhein 67056, Germany.
⁵ California Research Alliance (CARA) by BASF, Berkeley 94720, CA, United States.
⁶ Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara 93106, CA, United States.
⁷ Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara 93106, CA, United States. Electronic address: shell@ucsb.edu.
⁸ Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara 93106, CA, United States; Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara 93106, CA, United States; Department of Materials Engineering, University of California, Santa Barbara, Santa Barbara 93106, CA, United States. Electronic address: ghf@ucsb.edu.

PMID: 36736121
DOI: 10.1016/j.jcis.2023.01.015

Abstract

Hypothesis: The computational study of surfactants and self-assembly is challenging because 1) models need to reflect chemistry-specific interactions, and 2) self-assembled structures are difficult to equilibrate with conventional molecular dynamics. We propose to overcome these challenges with a multiscale simulation approach where relative entropy minimization transfers chemically-detailed information from all-atom (AA) simulations to coarse-grained (CG) models that can be simulated using field-theoretic methods. Field-theoretic simulations are not limited by intrinsic physical time scales like diffusion and allow for rigorous equilibration via free energy minimization. This approach should enable the study of properties that are difficult to obtain by particle-based simulations.

Simulation work: We apply this workflow to sodium dodecylsulfate. To ensure chemical fidelity we present an AA force field calibrated against interfacial tension experiments. We generate CG models from AA simulation trajectories and show that particle-based and field-theoretic simulations of the CG model reproduce AA simulations and experimental measurements.

Findings: The workflow captures the complex balance of interactions in a multicomponent system ultimately described by an atomistic model. The resulting CG models can study complex 3D phases like double or alternating gyroids, and reproduce salt effects on properties like aggregation number and shape transitions.

Keywords: Coarse-graining; Field theory; Formulations; Micelle; Microphase; Multiscale; SDS; Self-assembly; Simulation; Surfactant.

MeSH terms

Entropy
Molecular Dynamics Simulation*
Surface-Active Agents*

Substances

Surface-Active Agents