Film-forming amphiphilic silsesquioxane hybrids prepared by hydrolytic co-condensation of hydroxyl-functionalized and fluorinated triethoxysilanes

Abstract

Amphiphilic silsesquioxanes-based hybrids were synthesized by hydrolytic co-condensation of a hydroxyl-functionalized triethoxysilane precursor derived from 2-hydroxyethyl acrylate (HEA) and fluorinated triethoxysilane precursors derived from 1H,1H,5H-octafluoropentyl acrylate (OFPA) and 2,2,2-trifluoroethyl acrylate (TFEA). Hydrolytic co-condensations of two functionalized triethoxysilane precursors proceeded as homogeneous systems in N,N-dimethylformamide (DMF) to afford amphiphilic silsesquioxanes hybrids, which were soluble in a variety of solvents, depending on the composition. The structure of the constitutional unit of the hybrids was confirmed by the results of NMR and FT-IR measurements. Scanning force microscope (SFM) measurements indicated the formation of spherical hybrids having relatively narrow size distributions (average particle diameter < 3.0 nm) without aggregation. The sizes of the hybrids were also confirmed by X-ray diffraction (XRD). Flexible semitransparent films were obtained from the amphiphilic silsesquioxane hybrids prepared by hydrolytic co-condensations at suitable feed ratios. The organic-inorganic amphiphilites exhibited a high density of chemically bonded peripheral fluoroalkyl and hydroxyalkyl groups, in which various characteristic properties involving amphiphilicity, film-forming property, refractive index, responsive surface, nanometer size, and narrow size distribution can be manipulated by varying the composition in the feed.