Interactions of Crosslinked Polyacrylic Acid Polyelectrolyte Gels with Nonionic and Ionic Surfactants

Abstract

The morphology and stability of surfactant-loaded polyelectrolyte gels are of great interest for a variety of personal care, cosmetic, and pharmaceutical products. However, the mechanisms of surfactant interactions with gel-forming polymers are poorly understood and experimentally challenging. The aim of this work is to explore in silico the specifics of surfactant absorption within polyelectrolyte gels drawing on the examples of typical non-ionic octaethylene glycol monooctyl ether (C 8 E 8 ) and anionic sodium dodecyl sulfate (SDS) surfactants and polyacrylic acid modified with hydrophobic sidechains mimicking the practically important Carbopol polymer. Using the systematically parameterized coarsegrained dissipative particle dynamics models, we generate and characterize the equilibrium conformations and swelling of the polymer films in aqueous solutions with the surfactant concentrations varied up to the critical micelle concentration (cmc). We discover the striking difference in interactions of Carbopol-like polymers with nonionic and ionic surfactants under mildly acidic conditions. The sorption of C 8 E 8 within the polymer film is found substantial. As the surfactant concentration increases, the polymer film swells and, close to cmc, becomes unstable due to the formation and growth of water pockets filled with surfactant micelles. Sorption of SDS at the same bulk concentrations is found much lower, with only about 1% of surfactant mass fraction achieved at cmc. As the SDS concentration increases further, a lamellae structure is formed within the film, which remains stable. Reduced swelling and higher stability indicate better prospects of using SDS-type surfactants with Carbopol-based gels in formulations for detergents and personal care products.

Reproduction of super-multicomponent self-assembled structures and their functionality using coarse-grained molecular simulation – the example of cleansing agents

“…[44][45][46] In particular, in recent years DPD has been actively used to study selfassembly in multi-component systems. 37,47,48 There are also several studies which investigate the morphologies of surfactant solutions using molecular dynamics, 49 or coarsegrained molecular dynamics. 50,51 These methods can reflect hydrogen bonding and more detailed chemical structures compared to the DPD method, but at the same time, they have a large computational cost.…”

Transition in solution dynamics of polyacrylic acid: An interplay between nonergodicity and triple mode relaxation

“…This has given rise to the fabrication of numerous smart materials in the drug delivery and food industry for its environmentally stimulated conformational change with pH variation. From the wide application point of view, most of the studies of PAA are focused in gels or with surfactant mixtures or complex formation and adsorption properties [17][18][19][20][21] whereas the research in basic PAA solution are not many compared to the strong polyelectrolytes like, NaPSS or DNA. The structural and dynamical properties of polyelectrolyte solution are governed by electrostatic interactions which are considered as the strongest and long range interactions than the other regular kind of interactions in polymeric systems.…”

Nanogel Degradation at Soft Interfaces and in Bulk: Tracking Shape Changes and Interfacial Spreading

“…Since nanogels and microgels are soft polymer networks with characteristic linear sizes of the order of tens to hundreds of nanometers to tens of microns, respectively, mesoscale modeling approaches are commonly used to capture their behavior in solvents and at the interfaces. Dissipative particle dynamics (DPD), − a mesoscale approach that has been used for modeling a broad range of multi-component systems, − is often chosen to model behavior of microgels at liquid–liquid interfaces. ,,,− To model controlled degradation and erosion in hydrogels, we recently adapted a modified segmental repulsive potential (mSRP) to overcome unphysical crossing of polymer chains along with modeling of degradable bonds. , As a model polymer network, we focused on gels synthesized by the end-linking of four-arm polyethylene glycol (PEG) precursors − originally fabricated by Sakai et al. These precursors can be modified during their synthesis by including photodegradable functional groups, for example, nitrobenzyl − or coumarin , groups.…”