Effects of colloidal silica on the properties of POSS-containing fluorinated poly(styrene–acrylate)/SiO2 composite materials

Abstract

Polyhedral oligomeric silsesquioxane (POSS)-containing fluorinated poly(styrene–acrylate)/SiO2 (POSS-FPSA/SiO2) composite materials were prepared by preemulsification and direct blending method. The SiO2 particles were induced aggregated onto the surface of POSS, and sol–gel processes were simultaneously carried out with addition of co-solvent to form raspberry-like structure. 29Si NMR and XRD results confirmed that POSS were successfully grafted to polymer and were evenly dispersed uniformly in polymer matrix. The average diameter of composite latexes increased from 63 to 81 nm with increasing addition of SiO2 content. AFM and WCA images confirmed that sol–gel processes were promoted by increasing addition of SiO2 content, which improved the roughness and hydrophobicity of composite films. XPS spectra displayed that two kinds of Si–O bonds existed on the surface of composite films. One was related to the Si–O groups of SiO2, and the other was attributed to the Si–O–Si groups obtained from the sol–gel processes. The peak area of the former decreased from 56.86% to 38.78%, while the latter increased from 43.14% to 62.22%. TGA curves demonstrated that the composite film exhibited better thermal stability when the SiO2 content was 10.0%. In addition, serious phase separation would decrease the thermal stability of composite films.