Wetting effect of branched anionic Gemini surfactant aqueous solution on PMMA surface

In this paper, the adsorption behaviour and wetting modification ability of the sodium salts of bis-octadecenoyl succinate (GeminiC3, GeminiC6) and monomers on polymethyl methacrylate (PMMA) surfaces were investigated. The difference in spacer length led to slightly different behaviour of surfactant molecules in solution. The large molecular structure and short flexible spacer of GeminiC3 led to a complex self-aggregation behaviour in solution, forming micelles at low concentrations, leading to a rapid decrease in surface tension and subsequent transition to monolayer or multilayer vesicles. In GeminiC6, the longer flexible spacer groups act as spatial structure modifiers that hinder the formation of vesicles. The adsorption behaviour of the gas-liquid interface was analysed in three stages for the peculiar inflection points where surface tension appears. Combining contact angle measurements, adhesion tension and interfacial tension data showed that GeminiC3 and C6 formed a saturated monolayer on the adsorbed PMMA surface at low concentrations and a bilayer structure at high concentrations. Due to the low resistance of molecular space sites, the monomers adsorbed heavily on the PMMA surface, forming semi-colloidal aggregates with the lowest contact angle of monomeric surfactant solutions reaching 38 degrees on the PMMA surface. Also, the monomer and GeminiC3 and C6 surfactants in this paper have a very high hydrophilic modification ability on the PMMA surface compared to other literature.

Automated summary

This study investigated the adsorption behavior and wetting modification ability of sodium salts of bis-octadecenoyl succinate (GeminiC3, GeminiC6) and monomers on polymethyl methacrylate (PMMA) surfaces. The different spacer lengths resulted in slightly different behavior of surfactant molecules in solution. GeminiC3 exhibited complex self-aggregation behavior, forming micelles at low concentrations and transitioning to monolayer or multilayer vesicles. GeminiC6 had longer flexible spacer groups that hindered vesicle formation. Adsorption behavior at the gas-liquid interface was analyzed in three stages, showing a saturated monolayer and bilayer structure formed by GeminiC3 and C6 on PMMA surfaces. The monomers heavily adsorbed on PMMA surfaces and formed semi-colloidal aggregates, with the lowest contact angle reaching 38 degrees. Additionally, the monomers and GeminiC3/C6 surfactants demonstrated high hydrophilic modification ability on PMMA surfaces compared to other literature.