Effects of Preparation and Self-Assembly of Poly(Styrene-Acrylic Acid) (P(St-AA)) Microspheres upon Constructed Photonic Crystals with Structural Color on Wood Surfaces

Abstract

Colloidal microspheres could be used as raw materials to construct the photonic crystal modification layers on wood surfaces, and the wood would produce gorgeous structural color effect. The diameter, monodispersity and self-assembly of colloidal microspheres directly affect the well-structure order of photonic crystals. Therefore, poly(styrene-acrylic acid) (P(St-AA)) shell-core microspheres were prepared by emulsion polymerization. The effects of the reaction time, amount of initiator and emulsifier and reaction temperature on the particle size and dispersity of colloidal microspheres during polymerization were analyzed by single-factor experiments. The P(St-AA) colloidal microspheres self-assembled on wood surfaces and formed photonic crystals with structural color through thermally-assisted gravity deposition. The effects of the amount of emulsion coating per unit surface area and ambient temperature on the optical properties of the photonic crystals were investigated. It was found that the particle size of the synthesized microspheres increased with the increase of initiator amount and reaction temperature and the decrease of emulsifier; however, the effect of reaction time on microspheres was less regular. The best optical properties of the photonic crystals on wood surfaces were obtained using 0.408 μL/mm2 emulsion coating at a temperature of 50 °C. The photonic crystals were composed of both ordered and disordered layers.