Aggregation Structure and Surface Properties of Poly (Ethylene Maleimide) Copolymer Thin Film Modified with Fluoroalkyl and Alkyl Side Chains
Katsuhiro YAMAMOTO, Takeshi KONDO and Eri ITO
Abstract:We investigated the aggregation structure and surface properties of ethylene-maleimide copolymer thin films as a function of fraction of fluoride side group by means of small angle X-ray scattering (SAXS), grazing incidence SAXS (GISAXS), DSC, and contact angle measurements. The maleimide copolymers were synthesized through the imidization of poly(ethylene-alt-maleic anhydride) with stearylamine and fluoroalkyl amine. The thin films were obtained by spin-coating on silicon wafers and annealed at appropriate temperatures. The copolymer having fluoroalkyl side chains (SFx) form ordered structure when fluorine side chain content is more than 40%. The copolymer SFx attached with stearyl and fluoroalkyl side chains formed the layered structure no less than 40 mol% of fluoroalkyl side group. In the thin film, the layer was found to be aligned parallel to the substrate as revealed by GISAXS and AFM. The surface free energy of the SFx was revealed to decrease steeply around 40 mol% of fluoroalkyl side group. The surface segregation of the fluorine groups linked to the ordered structure formation. Key Words:Surface free energy, Fluoroalkyl side chain, Thin film, GISAXS, AFM, XPS