Controllable Surface and Optical Properties of Methacrylic Copolymer Films Using Various Monomer Combinations

Various fluorinated methacrylic copolymers (PFPMA- X) were prepared from 2,2,3,3,3-pentafluoropropyl methacrylate (PFPMA), methyl methacrylate (MMA), and three other nonfluorinated monomers. The surface and the optical properties of these copolymers were controlled by changing the ratio of PFPMA to MMA while keeping the sum of the concentration of the two monomers fixed at 60 wt %. The parameter X represents the nominal concentration of PFPMA in various feed ratios of all five monomers. Depending on the increase in PFPMA content in PFPMA- X, the surface energy varied proportionately between 26.7 (PFPMA content: 20 wt %) and 17.4 mN/m (PFPMA content: 60 wt %), which is well-correlated with the fluorine content on the surface. Interestingly, we found that all PFPMA- X-coated glasses showed different transmittance curves in the wavelength range of 300-700 nm, and the wavelength at which maximum transmittance was recorded shifted as a function of the copolymer composition. In addition, the surface coatings of PFPMA- X with higher fluorine contents increased the transmittance of bare glass by approximately 1-2%. Quite lower and tunable refractive indices were obtained depending on the fluorine content, and all PFPMA- X showed extremely lower birefringences. Freestanding films of PFPMA- X were also well-formed, indicating that they can be used in a wide range of applications.