# Predicting Critical Micelle Concentrations from Short Time Scale Simulations

## TL;DR

This paper introduces a method to predict surfactant CMCs using short simulations, reducing the need for long equilibration times.

## Contribution

A novel approach using short time scale simulations to predict surfactant CMCs based on the Aniansson–Wall model.

## Key findings

- The method successfully predicts CMCs for both charged and uncharged surfactants.
- Short time scale simulations can replace long equilibration runs without sacrificing accuracy.

## Abstract

The determination
of surfactant critical micelle concentrations
(CMCs) using molecular simulations is by now a well-established procedure.
The approach typically utilizes the equilibrium free surfactant concentration
(i.e., those surfactants not in micelles). However, equilibration
can be a slow process, particularly for surfactants with low CMC values,
requiring large amounts of compute resource even when coarse grained
approaches are adopted. We here explore the possibility of using incompletely
equilibrated short time scale runs to predict surfactant CMCs using
dissipative particle dynamics (DPD) simulations. We ground the methodology
in the Aniansson–Wall stepwise association model of micelle
kinetics, and apply it to a selection of uncharged (nonionic and zwitterionic)
and charged (ionic) surfactants. We find the approach to be useful
for predicting the CMC of both charged and uncharged surfactants.