Photochemical control over the wettability of the polymer surface and adsorption of the partially fluorinated and hydrocarbon surfactants at the polymer–solution interface

Abstract

The wettability of polymers has attracted considerable interest in recent years. Herein, we investigated the wettability of a polymethyl methacrylate (PMMA) surface, which was modified by a partially fluorinated gemini surfactant and a hydrocarbon gemini surfactant. The wettability of the PMMA surface could be controlled by UV irradiation. After UV irradiation, the interfacial tension at the PMMA–solution interface decreased, the surfactant adsorption on the PMMA surface reduced, and the adsorption film became more rigid. The contact angles of the Gemini surfactant began to decrease as the surfactant concentration increased to 5.0 × 10⁻⁵ mol L⁻¹ , which was far below their critical micelle concentrations (CMCs). Their changes in the contact angles are very different from those of conventional surfactants. The surfactants were present in higher excess concentrations at the air–solution interface than at the PMMA–solution interface. The partially fluorinated surfactant exhibited a higher adsorption capability on the PMMA surface than the hydrocarbon surfactant. The switchable adsorption of the surfactant on the PMMA surface was achieved by light irradiation.