Surface Fluorination of Silicone Rubber with Enhanced Stain Resistance and Slip Properties

Abstract

Silicone rubber (SR) holds significant potential for everyday wearable devices due to its inherent sweat resistance and flexibility. However, its broader applicability is constrained by poor oil resistance and a suboptimal slip performance. In this study, we developed an SR with durable oil resistance and enhanced slip properties by forming a covalently bonded barrier layer on its surface through a one-step in situ fluorination reaction using F₂/N₂. The fluorination process exploration revealed that low concentrations of F₂ preferentially produce thermodynamic products containing Si–F bonds, while higher F₂ concentrations favor the formation of C–F bonds and Si–F bonds with similar contents in the surface layer, as confirmed by theoretical simulations. This fluorine-containing surface modification significantly reduces the friction coefficient from 0.68 to 0.38 and imparts fascinating amphiphobic properties, increasing water and oil contact angles by 31.7 and 23.2°, respectively, compared to pristine SR. As a result, the fluorinated SR demonstrates superior slip performance and enhanced stain resistance, particularly against challenging contaminants like chili oil, even after frictional wear owing to the robustness of the covalently bonded surface layer. Additionally, the outstanding oil barrier properties of the fluorinated SR confer excellent antibacterial performance against Escherichia coli and Staphylococcus aureus, positioning it as a highly promising material for everyday wearable applications.