Surfactant chain length and concentration influence on the interfacial tension of two immiscible model liquids: a coarse–grained approach

Abstract

The interfacial tension between immiscible liquids is studied as a function of a model linear surfactant length and concentration using coarse-grained, dissipative particle dynamics numerical simulations. The adsorption isotherms obtained from the simulations are found to be in agreement with Langmuir's model. The reduction of the interfacial tension with increasing surfactant concentration is found to display some common characteristics for all the values of chain length modeled, with our predictions being in agreement with Szyszkowski's equation. Lastly, the critical micelle concentration is predicted for all surfactant lengths, finding exponentially decaying behavior, in agreement with Kleven's model. It is argued that these findings can be helpful guiding tools in the interpretation of available experiments and in the design of new ones with new surfactants and polymers.

Dissipative Particle Dynamics Study on Interfacial Properties of Symmetric Ternary Polymeric Blends

“…In the previous study, we utilized Monte Carlo simulation to examine the effects of diblock copolymer on the interfacial properties of A n / A m B m / B n polymeric blends [ 26 , 27 ], and illustrated that the interfacial width, density distribution, and orientation of the diblock copolymer strongly depended on the diblock copolymers’ chain properties. In recent years, dissipative particle dynamics (DPD) simulations became a vital tool for studying the physicochemical properties of polymeric blends, including phase behavior, dynamics, and morphology evolution [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. Specifically, Groot et al [ 41 ] employed DPD simulation to calculate the interfacial tension of immiscible polymer blends.…”

Effects of Repulsion Parameter and Chain Length of Homopolymers on Interfacial Properties of An/Ax/2BxAx/2/Bm Blends: A DPD Simulation Study

“…In a previous study, we employed the DPD method to investigate the effect of the chain length and concentration of triblock copolymer compatibilizers on the interfacial tension between two immiscible homopolymers [ 29 ]. The model of this work is constructed based on our previous work and other studies [ 8 , 9 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. Herein, we briefly introduce the model; interested readers could refer to these studies for the further development of the model.…”

“…For the conservative force , we simply choose for and for . Unlike and have a certain relation according to the fluctuation–dissipation theorem [ 31 ]: where and T represent the Boltzmann constant and the temperature, respectively. The weight functions of dissipative and random forces are simply chosen as the previous work of Groot and Warren [ 42 ]: …”

“…For the conservative force F C ij , we simply choose ω C r ij = 1 − r ij for r ij < 1 and ω C r ij = 0 for r ij ≥ 1. Unlike ω C r ij , ω D r ij and ω R r ij have a certain relation according to the fluctuation-dissipation theorem [31]:…”

The Effect of Mixtures and Additives on Dissolving Surfactant Lamellar Phases

“…Surfactants are amphiphilic molecules that consist of at least two parts: a hydrophilic (water-liking) head part and a hydrophobic (water-hating) tail part . They are classified according to their headgroup’s charge: nonionic, zwitterionic, anionic, and cationic .…”