Amphiphiles coordinated to block copolymers as a template for mesoporous materials

We show a concept where coordination of amphiphiles to one block of a block copolymer leads to polymeric supramolecules and self-organization and that mesoporous materials can be achieved with a dense set of polymer brushes at the surfaces upon cleaving the amphiphiles by extraction with a selective solvent. Polystyrene-block-poly(4-vinylpyridine) (PS-block-P4VP) is used with zinc dodecylbenzenesulfonate (Zn(DBS)(2)) which can coordinate to the lone electron pairs of the pyridine nitrogens in the P4VP block, leading to complexes PS-block-P4V-P[Zn(DBS)(2)](y). Coordination of Zn(DBS)(2) and structure formation were investigated using Fourier transformation infrared spectroscopy (FTIR), small- and wide-angle X-ray scattering (SAXS and WAXS), and transmission electron microscopy (TEM). Lamellar structure was observed and even points toward a structural hierarchy for high molecular weight block copolymers. FTIR, SAXS, and TEM showed that most of Zn(DBS)(2) can be extracted from such templates using methanol, leading to lamellar porous structures. P4VP brushes cover the resulting pore surfaces. The structures do not collapse probably due to the glassy PS and defects in the nonaligned structure. Compared to hydrogen bonding, coordination allows bonding of higher molecular weight amphiphiles due to the stronger attraction.