Highly transparent multifunctional bilayer coatings on polymers using low-temperature atmospheric plasma deposition

We report on the synthesis of hard, adhesive, and highly transparent bilayer organosilicate thin films on large poly(methyl methacrylate) substrates by atmospheric plasma, in ambient air, at room temperature, in a one-step process, using a single precursor. The method overcomes the challenge of fabricating coatings with high mechanical and interfacial properties in a one-step process. The bottom layer is a carbon-bridged hybrid silica with excellent adhesion with the poly(methyl methacrylate) substrate, and the top layer is a dense silica with high Young’s modulus, hardness, and scratch resistance. The bilayer structure exhibited ~100% transmittance in the visible wavelength range, twice the adhesion energy and three times the Young’s modulus of commercial polysiloxane sol–gel coatings.