FT-IR Imaging of Patterned Photocrosslinkable Poly(Vinyl Cinnamate)

The use of photocrosslinkable polymers and photomasks was proposed as a means of reducing the number of raw materials necessary to create a chemical sensor array. To test this hypothesis, poly(vinyl cinnamate) was crosslinked to various degrees with the use of a photomask, exposed to a binary solvent vapor of benzonitrile and dimethyl formamide, and examined by FT-IR imaging. The results illustrate that FT-IR imaging is effective for visualizing the patterning of the crosslink density of a polymer film as well as the temporal and spatial sorption patterns of different solvent vapors. The FT-IR images show that the decrease in sorption capacity with crosslink density is solvent-specific, which suggests that photocrosslinkable polymers can be used to reduce the number of raw materials needed to create a chemical sensor array. The potential disadvantage of using glassy polymers as chemical sensors is also demonstrated by the temporal FT-IR images of solvent desorption.