Bulk and Surface Properties of Maleimide Copolymers:  Effect of Fluorinated Side Chains

We studied the bulk and surface properties of maleimide (MI) copolymers based on three different main chains, poly(ethene-alt-maleimide), poly(styrene-alt-maleimide), and poly(octadecene-alt-maleimide), with two different types of side chains (4-(N-perfluoroheptylcarbonyl)aminobutyl and n-dodecyl). By the given alternating substitution pattern of the side chains in MI copolymers, different side chain organizations caused different surface energetics. On the basis of determined advancing contact angles of water on spin-coated MI copolymer films, solid surface tensions γ sv were calculated in the range of 19−23 mJ/m2 for alkyl side chains and of 11−18 mJ/m2 for fluorinated side chains. In both cases, within the aliphatic and fluorinated series, the main chain poly(styrene-alt-maleimide) suppressed a better alignment of side chains resulting in nondensely packed CH3 and CF3 surface groups, respectively, and higher solid surface tensions. For this study small- and wide-angle X-ray diffraction, differential scanning calorimetry, attenuated total reflection infrared spectroscopy, ellipsometry, atomic force microscopy, contact angle measurements, angle-resolved X-ray photoelectron spectroscopy, and molecular modeling calculation were used to investigate the bulk and surface properties.