Seed colloidal core particles (CCPs) were prepared by surfactant-free emulsion polymerization of tert-butyl methacrylate and the cross-linker ethylene glycol dimethacrylate (EGDMA) initiated by potassium persulfate. Core-shell particles (CSPs) were then synthesized by the encapsulation of the CCPs via the living radical polymerization of methyl methacrylate, EGDMA, and N,N-diethyldithiocarbamate. These CSPs present surface photofunctional dithiocarbamate groups. Core-poly(methyl methacrylate) brush particles (CBPs) were then prepared by photoinduced atom transfer radical polymerization of MMA initiated by CBP macroinitiators in the presence of a CuCl/bpy catalyst. Colloidal crystals were constructed using these particles and novel locking methods for these colloidal crystals were established. Their optical properties were investigated by measuring their reflection spectra from a viewpoint of structural colors. As a result, structural colors were strongly dependent on particle size (D-s) and effective refractive index (n(eff)). POLYM. ENG. SCI., 58:1698-1702, 2018. (c) 2017 Society of Plastics Engineers