Preparation and characterization of transparent polyarylethers-silica hybrid membranes with covalently connected phases

From the molecular designing point of view, (p-amino)phenylhydroquinone (APH) and (3, 5-dimethoxy)phenylhydroquinone (DMPH) were prepared in a two-step synthesis. Polyetheretherketone with a large number of amino groups (APEEK) and polyethersulfone with quantities of hydroxyl side groups (HPES) were successfully synthesized from these bisphenol monomers. The functionalized polyarylethers were then grafted by isocyanatopropyltriethoxysilane (IPTS) through in-situ O-acylation reaction to obtained triethoxysilyl groups. Subsequently, these hydrolyzed triethoxysilyl groups formed network and produced covalent bonds between organic and inorganic phases via a sol–gel process under acid condition. Transparent polyarylether-silica (PAE-silica) hybrid films were fabricated through this in-situ sol–gel process. Furthermore, tetraethylorthosilicate (TEOS) and SiO2 nanoparticles were introduced as silica sources to improve the content of silica. The in-situ generated SiO2 by hydrolysis of the silica sources with triethoxysilyl groups on IPTS modified polyarylethers was covalently connected with the substrates. The present method achieved transparent hybrid films at high silica content of 40 wt%, which was resulted from inorganic and organic phases closely combination and homogenous distribution of silica particles in the polymer matrix.