Molecular dynamics simulation on the structure–activity relationship between the Gemini surfactant and foam properties

Abstract

The structure-activity relationship between the molecular structure of Gemini surfactants and foam properties has not yet been deeply revealed. In this study, we clarified for the first time the structure-activity relationship between foam properties and molecular structure of Gemini surfactant by discussing the variation characteristics of parameters such as free energy of interface formation, radial distribution function, and mean square displacement calculated by molecular simulation method. The research results show that (1) the Gemini surfactant with the sulfonic acid head group has the most excellent foam properties; (2) the foam properties increase monotonously with the increase of the hydrophobic tail chain length; (3) the foam properties decrease monotonously with the increase of the spacer group length. It is hoped that this article can further broaden the application range of surfactants as foaming agents in industrial fields such as oil and gas exploitation.

Renewable dissymmetric sulfonate gemini surfactants from addition of sodium hydrogensulfite to alkyl linoleate

“…As presented in Table 3, compared with SELD and SBLD, the SMLD molecule has a higher minimum molecular adsorption area ( A min ), which inevitably leads to looser arrangements of its molecules at the air/aqueous solution interface. On the other hand, for surfactants with the same hydrophilic group and hydrophobic chains of different lengths, increasing hydrophobic chain length renders them more hydrophobic, such that more of their molecules are adsorbed at the interface in closer proximity, resulting in increased foam stability 32,58 . Concerning the bubble photographs shown in Figure 7C, SBLD induced the bubbles with smaller and more count than SELD and SMLD.…”

Law and Mechanism Study on Salt Resistance of Nonionic Surfactant (Alkyl Glycoside) Foam

“…In recent years, molecular dynamics (MD) simulation has gradually become an important way to study foam stability at the molecular scale [20]. In previous MD studies, the stability of foam was studied mainly through the following aspects: the structural characteristics of surfactant monolayer [21], the distribution characteristics of molecules [22,23], the interactions between groups (molecules) and other groups (molecules) [24,25], and the interaction energy between different molecules [26,27]. Many researchers have studied the interfacial formation energy (IFE) [23,28] of foam, the potential of mean force (PMF) [29], diffusion coefficient (d) [28], and so on [30], hoping to introduce quantitative parameters for research.…”