Poly[styrene-b-maleated (ethylene/butylene)-b-styrene] (mSEBS) block copolymers and mSEBS/inorganic nanocomposites: I. Morphology and FTIR characterization

Self-assembled, [block copolymer]/[pure silicate and ORMOSIL] nanocomposites were created via sol–gel processes for silicate and organically-modified silicate (ORMOSIL) monomers in the presence of sulfonated maleated poly(styrene-b-ethylene/butylene-b-styrene) (mSEBS). Microscopic and small angle X-ray scattering (SAXS) studies showed that unmodified mSEBS has hexagonal packed PS cylinder morphology, but sulfonation causes the morphologies to be frustrated. The morphology of pure silicate nanoparticle-containing nanocomposites is phase separated, although further frustrated. The morphologies of the ORMOSIL-modified materials were different, less-ordered and show the influence of the nature of the organic group on self-assembly. Despite differences in morphology, degree of order, and different inter-domain spacings, all but the pure silicate-containing hybrid have the same PS domain width (25–30 nm). The dispersed nanoparticles are roughly spherical and some can grow to exceed the block copolymer domain sizes. All filled samples have inter-domain spacings, derived by SAXS analysis, that are larger than that of the corresponding unfilled sulfonated mSEBS, which reflects insertion of silicate or ORMOSIL structures. FTIR spectroscopy indicated successful Si–O–Si bond formation, which shows that the inserted particles are indeed crosslinked.