Hybrid organic–inorganic membranes from size exclusion deposition of fluorescent, octylene-bridged polysilsesquioxane particles

Abstract Hybrid organic–inorganic membranes were prepared by size exclusion deposition of fluorescent, octylene-bridged polysilsesquioxanes (OBP) nanoparticles onto ceramic membrane supports. Acid-catalyzed, sol-gel polymerization of 1,8-bis(triethoxysilyl)octane (BESO) was shown by dynamic light and scattering electron microscopy to afford spherical nanoparticles that, after 3–4 weeks, were sufficiently large enough to block the pores in porous, ceramic membranes with a 1.5 nm cut-off. The OBP particles were deposited by drawing a low concentration sol through the ceramic membrane. The OBP particles blocked the pores with an intractable, tightly packed layer 3 μm in thickness. The efficacy of size exclusion deposition was verified by incorporation of small amounts of a fluorescent, dansyl co-monomer into the particles and inspection of the membrane cross section by confocal fluorescence microscopy.