Microfluidic synthesis of silica microcomponents using sol-gel process and stop-flow lithography

Abstract

Abstract We have developed a simple and economical method for synthesizing silica microcomponents by combining sol-gel process and stop-flow lithography. In this method, a dual-cure system containing hydrogel monomer and silica precursor was prepared as the precursor solution. The production of particles then involves a photopolymerization step and a sintering step. The former defines the shape of the microcomponents by stop-flow lithography and the latter is responsible for promoting the sol-gel process and decomposing the hydrogel. The sintered silica microcomponents shrink significantly but have a Young's modulus as high as 30 Gpa, a value much higher than that of typical polymeric materials and close to that of pure silica. By adding superparamagnetic particles into the precursor solution, we also manufactured magnetic silica gears that can be driven remotely by an external magnetic field. Owing to the generality of the sol-gel process, this method is expected to have great potential for producing microcomponents of other metal oxides.