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

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.