Simulations of a lattice model of two-headed linear amphiphiles: Influence of amphiphile asymmetry

Abstract

Using a 2D lattice model, we conduct Monte Carlo simulations of micellar aggregation of linearchain amphiphiles having two solvophilic head groups. In the context of this simple model, we quantify how the amphiphile architecture influences the critical micelle concentration (CMC), with a particular focus on the role of the asymmetry of the amphiphile structure. Accordingly, we study all possible arrangements of the head groups along amphiphile chains of fixed length N = 12 and 16 molecular units. This set of idealized amphiphile architectures approximates many cases of symmetric and asymmetric gemini surfactants, double-headed surfactants and boloform surfactants. Consistent with earlier results, we find that the number of spacer units s separating the heads has a significant influence on the CMC, with the CMC increasing with s for s < N/2. In comparison, the influence of the asymmetry of the chain architecture on the CMC is much weaker, as is also found experimentally.

Asymmetric cationic gemini surfactants: an improved synthetic procedure and the micellar and surface properties of a homologous series in the presence of simple salts

“…Gemini, or dimeric surfactants, have two matching head groups connected by a linking chain, the most common being an alkylene chain; [1][2][3][4][5][6][7][8] the hydrophobic tails of the head groups may be the same (symmetric gemini surfactant) or different (asymmetric gemini surfactant). The symmetric members of the cationic gemini surfactants listed in the above references are the most commonly studied in the literature, [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] whereas anionic, [25][26][27][28][29][30][31] zwitterionic, [32][33][34] and nonionic gemini [35][36][37] surfactants are comparatively less studied.…”

Monte Carlo simulation and theoretical approach to mixed surfactant system consisting gemini and conventional surfactants in aqueous solutions

“…Table 1 summarizes the interaction energies chosen for this study. It should be mentioned that the interaction parameters values we used are close to Poole and co-workers parameters [31].…”

“…These states are selected to be the equilibrium configurations and the aggregates are characterized in these states. Aggregates are defined as clusters that each tail, head, and spacer in them has at least one contact with another adjacent chain element [31]. All the mixed micelles that must be investigated.…”

“…In that study, the effect of gemini tail length on the composition of the formed micelles, the aggregation number, and deviation from the ideal behavior of the mixed surfactant systems have been investigated. The simulation of pure gemini surfactant system using Monte Carlo method has also been performed by a few researchers [29][30][31].…”

On the Difference between Self‐Assembling Process of Monomeric and Dimeric Surfactants with the Same Head to Tail Ratio: A Lattice Monte Carlo Simulation

“…Recently, Davis and Panagiotopoulos have used grand canonical Monte Carlo simulation of mixture of one-tailed and double-tailed nonionic amphiphile to study the effect of addition of a micellizing amphiphile on the behavior of another phase separating amphiphile [15]. Very recently, Jackson et al investigated assembling processes of two-headed linear surfactants by two dimensional lattice Monte Carlo simulations [16].…”