Azobenzene-siloxane hybrids with lamellar structures from bridge-type alkoxysilyl precursors

作者:Guo Sufang; Chaikittisilp Watcharop; Okubo Tatsuya; Shimojima Atsushi*
来源:RSC Advances, 2014, 4(48): 25319-25325.
DOI:10.1039/c4ra01709a

摘要

Lamellar azobenzene-siloxane hybrids were prepared by controlled hydrolysis and polycondensation of three types of precursors, where azobenzene is sandwiched by mono-, di- and triethoxysilyl groups using propylene linkers. All precursors underwent reversible and fast trans-cis isomerization upon UV/Vis irradiation in dilute solution. Upon hydrolysis of the triethoxysilylated precursor in a homogeneous solution under acidic conditions, precipitation occurred by self-assembly of hydrolyzed monomers into a lamellar structure. Although di- and mono-ethoxysilylated precursors produced less ordered products under identical conditions, highly ordered lamellar films were obtainable either by evaporation induced self-assembly of the hydrolyzed monomers or by solid-state reactions of precursor films. The degree of trans-cis isomerization of azobenzene moieties in the hybrid films was enhanced by decreasing the cross-linking degree of siloxane networks using precursors with less condensable alkoxy groups.

  • 出版日期2014

全文