Highly transparent cross-linked fluorinated polysiloxane coatings resisting CWAs simulants: Prepared via UV-triggered thiol-ene click reaction

Chemical warfare agents (CWAs) are highly toxic and prone to penetrate into and damage the coatings of various facilities, equipment, etc., which could also pose potential hazards to personnel. Developing protective coatings with good anti-penetration, transparency, and slipperiness properties remains a challenge. In this paper, a novel kind of coatings with both anti-penetration and liquid-like functions were prepared through the strategy of grafting fluorinated side chains as molecular brushes onto the cross-linking network. A fluorinated polysiloxane containing sulfhydryl groups was first synthesized and a series of polysiloxane coatings were prepared through UV-triggered thiol-ene click reaction employing different types of olefins crosslinkers. The coatings cured with trimethylcyclotrisiloxane and tetraallylsilane exhibited superior anti-penetration properties for simulants, due to their higher glass transition temperatures, increased crosslink density, smaller free volume and the lack of groups interacting strongly with simulants. These two coatings also exhibited liquid-like properties owing to the smooth surface and the presence of fluorine-containing segments, enabling the simulants slide down the tilted surface with almost no contaminated traces left on the coatings. The high transparency of the coatings would broaden the application prospects of these coatings. This article provides promising alternatives for polysiloxane-based protective coating materials.