Rapid fabrication of SiO2-PHEMA photonic crystal hydrogel composite microspheres

Abstract

Traditional photonic crystal microspheres have internal pores and can only be fabricated by self-assembly of colloidal nanoparticles. Therefore, their internal vulnerability to contamination and poor structural stability limit their further application. Therefore, we proposed a new method of photonic crystal composite microsphere fabrication by combining polymerisation with the self-assembly process. The droplets composed of colloidal nanoparticles, monomer, and initiator in continuous phase are obtained by a Shirasu porous glass (SPG) membrane emulsification undergo polymerised and self-assembled to obtain organic-inorganic photonic crystal composite microspheres. Since the self-assembled colloidal nanoparticles are immobilized in the polymer cross-linked network, the composite microspheres exhibit high structural stability. Based on this, we fabricated SiO2-PHEMA photonic crystal composite microspheres by polymerisation and self-assembly process. Compared with the pure SiO2 photonic crystal microspheres fabricated by the same method, the composite microspheres exhibit high structural stability, color saturation, and good hydrophobicity due to the self-curling of the material driven by hydrogen bonding during polymerisation. In addition to the potential applications as dyes, biosensors, and in light, these composite microspheres overcome the difficulty of bulk generation of traditional photonic crystal microspheres and have the potential for industrialized mass production.