Formation of an adsorbed monolayer from pentafluorophenyltriethoxysilane and its antisticking property to a UV-curable resin studied by high-sensitive UV-visible spectroscopy

Surface modification of a fused silica substrate was carried out by chemical vapor surface modification (CVSM) with (pentafluorophenyl) triethoxylsilane (F5Ph). The adsorption behavior of F5Ph was studied by high-sensitive UV-visible spectroscopy, contact angle measurement, and atomic force microscopy. The F5Ph adsorption on a silica substrate reached to the saturation by CVSM at 150 °C for 2 h. As a result, the adsorbed monolayer without aggregates was formed. The antisticking property of the F5Ph-adsorbed silica substrate to UV-curable resin causing radical photopolymerization was investigated. After curing and detaching a droplet of the resin, some organic components derived from the resin remained. The amount of remaining resin components on the F5Ph-adsorbed silica substrate was almost the same as that measured on silica substrates modified with (3,3,3-trifluoropropyl)trimethoxysilane (FAS3) and Optool-DSX forming antisticking layers. These results indicate that the F5Ph adsorbed monolayer is available as an antisticking layer in UV nanoimprint lithography. It was clear that high-sensitive UV-visible spectroscopy was a powerful tool to quantify adsorbed molecules on a silica mold surface and detect the adhesion of resin components after detachment.