Superhydrophobic and fluorescent properties of fluorinated polypyrene surfaces using various polar linkers prepared via electropolymerization

Superhydrophobic and fluorescent polypyrene surfaces were synthesized by an electropolymerization process. Six different linkers (ester, thioester, amide, carbamate, thiocarbamate and urea) are used to introduce fluorinated chains (lengths of 4, 6 and 8 carbons) onto pyrene moiety. The electropolymerized surfaces were analyzed by their morphology, surface chemistry, wettability and fluorescence. The linkers and the length of the fluorinated chain influence on both surface chemistry and morphology confirmed by XPS and SEM analysis, respectively. Superhydrophobic surfaces were obtained for ester, thioester, carbamate and thiocarbamate series while high hydrophobic surfaces for amide and urea series. Here, we show the possibility to control the surface hydrophobicity, oleophobicity and liquid adhesion with both the linker and the fluorinated chain length. For example, N-H groups seem to induce a decrease in the static contact angle (theta(w)) and in the surface structuration due to their polarity generating smoother surfaces (as for amide and urea series) and yielding to a red-shift in the emission spectra (showed for amide, carbamate, thiocarbamate and urea). The emission of all the polypyrene films is red-shifted compared to the pyrene monomers (excimer emission) and in the green region independently of the side chain. Here, we show that the nature of the heteroatom that connects the pyrene moiety to the fluorinated chain also does great impact on the surface morphology, wetting and fluorescence properties.