Nanostructures and surface hydrophobicity of epoxy thermosets containing hepta(3,3,3-trifluropropyl) polyhedral oligomeric silsesquioxane-capped poly(hydroxyether of bisphenol A) telechelics

Hepta(3,3,3-trifluoropropyl) polyhedral oligomeric silsesquioxane (POSS)-capped poly(hydroxyether of bisphenol A) (PH) telechelics was synthesized via Mannich condensation reaction among 4-aminobutyl-hepta(3,3,3-trifluoropropyl) POSS, phenolic hydroxyl-terminated poly(hydroxyether of bisphenol A) (PH) and formaldehyde. The POSS-capped PH amphiphile was incorporated into epoxy to access the nanostructures in the thermosets. Atomic force microscopy (AFM) showed that the epoxy thermosets possessed the microphase-separated morphologies. The formation of the nanostructures has been interpreted in terms of the self-assembly behavior of POSS-capped PH telechelics in epoxy thermosets. The glass transition temperatures (T-g's) of the nanostructured thermosets were quite dependent on the content of POSS-capped PH telechelics. Static contact angle measurements indicate that the POSS-containing nanocomposites displayed a significant enhancement in surface hydrophobicity as well as reduction in surface free energy. The improvement in surface properties was ascribed to the enrichment of POSS moiety on the surface of the nanostructured thermosets, which was evidenced by X-ray photoelectron spectroscopy (XPS). (C) 2011 Elsevier Inc. All rights reserved.