Block Copolymer−Ceramic Hybrid Materials from Organically Modified Ceramic Precursors

Abstract

The study of amphiphilic polymer based functional organic−inorganic hybrid materials is an emerging research area offering enormous scientific and technological promise. Here, we show that employing poly(isoprene-block-ethylene oxide) block copolymers (PI-b-PEO) and a silicon precursor, which contains a polymerizable organic moiety, unprecedented morphology control on the nanoscale is obtained. This control is based on a unique polymer−ceramic interface, which is characterized using a multi-nuclei solid-state NMR approach. The results show that the hydrophilic parts of the polymer are completely integrated into the ceramic phase, thereby leading to a quasi “two-phase system”, allowing for a more rational hybrid morphology design based on the current understanding of the phase behavior of block copolymers and copolymer−homopolymer mixtures. Examination of the full phase space of the hybrid materials reveals the existence of a new bicontinuous cubic structure that was not known to exist in polymer systems. SAXS and TEM data of this structure are consistent with a so-called “Plumber's nightmare” morphology. Selective solvent swelling of the hydrophobic parts of the hybrids leads to isolated nano-objects of different shapes, sizes, and compositions, while heat treatment generates mesoporous ceramic materials in which the mesostructure of the precursor material is preserved. Potential applications of these materials ranging from nanobiotechnology to catalysis are discussed.