Facile Synthesis of Robust Hybrid Xerogels by an Emulsion Assistant Method

Abstract In this study, we report a convenient one-pot synthesis of silsesquioxane hybrid xerogels with excellent mechanical flexibility by using copolymer emulsion as templates. During the acid-catalyzed sol-gel process of the precursors, the random copolymers of n-butyl methacrylate (n-BMA) and hydroxyethyl methacrylate (HEMA), not only suppressed macroscopic phase separation but also were incorporated in the skeleton of polysilsesquioxane by synergistic physical and chemical interactions. The resultant gels could be directly dried via ambient-pressure drying (APD) to gain xerogels without visible volume shrinkage. This unique preparation process is economical and environment-friendly without involving any organic solvents. The morphology and physicochemical performance of the monolithic hybrid xerogels can be readily tailored by changing the compositions and the concentrations of silsesquioxanes and copolymers in the reaction solutions. Xerogels fabricated from methyltrimethoxysilane showed excellent thermal insulation property, inherently superhydrophobicity, and outstanding mechanical strength against compression up to 50 MPa. Besides, the compressed specimen could recover its original shape by immersing in solvents and subsequently drying.