Impact of polyelectrolyte‐surfactant interactions on the rheology and wet lubrication performance of conditioning shampoo

Abstract

Objective The purpose of this study is to understand the impact of the cationic polymer merquat on the rheological behavior of the mixed surfactant system of sodium lauryl ether sulfate (SLES) and cocamidopropyl betaine (CapB) as well as the impact of varying formulation conditions on the wet lubrication performance of the SLES‐CapB‐Merquat system. Methods Rotation mechanical Rheometry was used to study the rheological response of the SLES‐CapB‐Merquat systems. Frequency sweeps were conducted to analyze the rheological properties of the system at low frequency ranges and bulk viscosity of the system was studied at high shear rates at varying salt and polymer concentrations. Wet combing tests and hair friction tests were run on the Dia‐stron MTT175 flexible miniature tensile tester in order to evaluate the conditioning effects of the different formulations. Results The SLES‐CapB system on its own exhibits very little viscosity. The bulk rheology results show that the addition of Merquat enhances the viscosity and viscoelastic properties of the SLES‐CapB‐Merquat system indicating the presence of electrostatic interactions between the surfactant and polyelectrolyte. Addition of salt had a significant impact on the system’s rheological response due to the charge screening effect of salt. Wet combing force data indicate that the charged polyelectrolyte binds to the hair substrate resulting in reduced combing force values after the product was applied. The addition of silicone oil to the formulation seemed to greatly enhance the conditioning effect of the formulation. Conclusion The charge interactions between SLES, CapB and Merquat results in the formation of an integrated gel like network, thus building the viscosity of the system. Variation of parameters like polymer and salt concentration has the potential to modify the bulk rheological properties and consequently the wet lubrication properties of the system.

Hybrid Field Theory and Particle Simulation Model of Polyelectrolyte–Surfactant Coacervation

“…16,17 In addition to the competition between these interactions, the multicomponent nature of these systemswhich consist of the polyelectrolyte, the surfactant molecules, both cation and anionic salt species, and watergives rise to a number of desirable properties that can be readily tuned. 20−22 Most importantly, phase behavior and self-assembly give rise to rheological properties such as foamability, wettability, and lubrication which are commonly used to engineer the sensorial properties 8 important for consumer applications (i.e., personal care and food products). Despite the key industrial role of this class of materials, there remain significant gaps in the community's knowledge of the fundamental physics governing the phase behavior of polyelectrolyte−surfactant mixtures.…”

“…Solutions of oppositely charged polyelectrolytes and surfactants have been studied extensively for a variety of applications, including drug encapsulation, − personal care products, − and food products. − These systems are known to exhibit a number of self-assembly or phase behaviors, driven by a complicated interplay of various intermolecular forces, particularly hydrophobic and electrostatic interactions. − Hydrophobicity drives the self-assembly of surfactant molecules into micelle structures, , and both hydrophobic and electrostatic interactions can promote the complexation of the polyelectrolytes with the oppositely charged surfactants. , In addition to the competition between these interactions, the multicomponent nature of these systemswhich consist of the polyelectrolyte, the surfactant molecules, both cation and anionic salt species, and watergives rise to a number of desirable properties that can be readily tuned. − Most importantly, phase behavior and self-assembly give rise to rheological properties such as foamability, wettability, and lubrication which are commonly used to engineer the sensorial properties important for consumer applications (i.e., personal care and food products). Despite the key industrial role of this class of materials, there remain significant gaps in the community’s knowledge of the fundamental physics governing the phase behavior of polyelectrolyte–surfactant mixtures.…”

Automated pipetting robot for proxy high-throughput viscometry of Newtonian fluids

“…[1][2][3][4] Viscosity, which describes the internal friction within a moving uid, is a key physical property of a wide range of products. Understanding the ow behavior is critical for product development in a range of sectors, including the consumer care, [5][6][7][8][9] oil and gas, [10][11][12][13][14] and pharmaceutical industries. [15][16][17] The ability to quickly screen for viscosity is therefore a valuable tool in accelerating the oen laborious, expensive, and time-consuming research and development cycles that companies currently face.…”

Study of the Dilution-Induced Deposition of Concentrated Mixtures of Polyelectrolytes and Surfactants

“…It has been previously shown that two-phase systems (2 ) are also obtained when the surfactant concentration is increased from highly diluted surfactant + polyelectrolyte mixtures [ 5 , 6 , 7 , 8 , 9 ]. This phase separation leads to the depletion of colloidal aggregates (solid-like or liquid-like) from the aqueous phase, resulting in their deposition on the solid surface which in turn is fundamental for defining the final performance of the formulations [ 10 , 11 , 12 , 13 ]. Therefore, it is possible to assume that the performance of most of the currently commercialized polyelectrolyte + surfactant formulations is mediated by the appearance of an enhanced deposition as the result of a dilution-induced precipitation process, the so-called Lochhead effect [ 1 , 14 , 15 ].…”