Surface Structure of Spin-Coated Fluorinated Polymers Films Dominated by Corresponding Film-Formation Solution/Air Interface Structure

In this paper, the relationship between the surface structures of spin-coated fluorinated polymer films and their corresponding film-formation solution/air interface structures was investigated. Film-forming poly(n-alkyl methacrylate) end capped with 2-perfluorooctylethyl methacrylate (FMA; PFMA(y)-ec-PnAMA(x)-ec-PFMA(y)) was synthesized via a controlled/living atom-transfer radical polymerization (ATRP) technique. The structures both at solution interface and on the spin-coated film surface for these polymers were studied by X-ray photoelectron spectroscopy (XPS), sum frequency spectroscopy (SFG), and surface tension measurements. The results showed that, with increasing polymerization degree of PnAMA, the fluorinated moieties in PFMA(y)-ec-PnAMA(x)-ec-PFMA(y) adsorbed at the solution/air interface were gradually completely replaced by PnAMA segments, resulting in an increase in corresponding solution surface tension until it was equal to that of poly(n-alkyl methacrylate) solution. Additionally, it was observed for the first time that the surface F/C ratios of spin-coated films decreased linearly with increasing surface. tension of the corresponding film formation polymer solution. Overall, the results indicate that the ultimate surface composition of spin coated films of these fluorinated methacrylates was mainly dominated by their corresponding film formation solution/air interfacial structure. This work provides a fundamental understanding of the formation of film surface. structures from fluorinated polymer solution to the resulting solid film.