Studies on the properties and molecular dynamics simulations of nonionic surfactants based on succinic acid derivatives

Abstract

Nonionic surfactants have proven useful in various applications such as wastewater treatment, enhanced oil recovery, dyeing, and cosmetics. Novel nonionic surfactants such as PEMP, BEMP, HEMP and BEEP were synthesized based on succinic acid derivatives and using L‐isoleucine as the linking group and four polyether alcohols as the hydrophilic group. First, the structures of the four nonionic surfactants were studied using Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectra. Then the critical micelle concentration (CMC) and surface tension at CMC (γCMC) of the four nonionic surfactants in aqueous solution were tested. γ‐lg c curves determined the relationships of their surface properties as BEEP > PEMP > BEMP > HEMP. In order to expand the range of applications for nonionic surfactants, we evaluated the salt‐resistant properties of four such surfactants. Our findings demonstrated that this class of surfactants indeed has superior salt‐resistant properties. Molecular dynamics (MD) simulations were used to study how surfactant molecules aggregate in the interfacial film. The study investigated the trend of solvent accessible surface area (SASA) over time. Results showed that the surfactant molecules interacted well with solvent molecules in the equilibrium state. This study investigates the performance differences among four types of surfactants using the electrostatic potential (ESP) distribution of their molecules. The study employed both experimental and computational simulations to provide a more comprehensive understanding of surfactant properties. The results offer insights into the theoretical research and application extension of this class of surfactants.