POSS-based glycidyl methacrylate copolymer for transparent and permeable coatings

Polyhedral oligomeric silsesquioxane (POSS)-based glycidyl methacrylate (GMA) hybrid copolymers of P(GMA-MAPOSS) are prepared by methacrylisobutyl polyhedral oligomeric silsesquioxane (MAPOSS) and GMA via free radical polymerization used as coatings. Their morphologies and particle size distributions in CHCl₃ solution are characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The effect of MAPOSS content on surface wettability, transparency and permeability of casted films, the adhesive strength, and thermostability of hybrid copolymers are further characterized by scanning electron microscopy (SEM), static contact angle (SCA), UV-Vis, mercury porosimeter, mechanical testing, differential scanning calorimetry (DSC), and thermogravimetry (TGA). Compared with the homogeneous surface of PGMA film, the surface of P(GMA-MAPOSS) film exhibits heterogeneous morphology due to the bulky volume of MAPOSS tending to agglomerate onto the film surface. This micro-rough structure helps to enhance the surface hydrophobicity (100–112° water SCA). While the surface of cured P(GMA-MAPOSS) film obtains a very homogeneous micro-rough morphology without any agglomeration due to the restricted movements of MAPOSS by 250 nm core-shell particles in CHCl₃ solution. Therefore, the cured P(GMA-MAPOSS) film provides with superior luminousness (>98%), strong adhesive strength (748.2 Pa), and high thermostability (T_g = 115°C). Particularly, the chemically involved MAPOSS into PGMA can effectually improve the permeability of traditional epoxy resin. It is believed that the POSS-based GMA hybrid copolymers P(GMA-MAPOSS) will have great potential applications as transparent and permeable coatings.