Narrow disperse core-brush polymer nanoparticles (BP) were synthesized by grafting from photo-induced atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate (HEMA) from N,N-diethyldithiocarbamate (DC) groups of core-shell particle surface. We constructed colloidal crystals of these particles by depositing on glass substrate. By variation of the particle size, the brilliant color could be varied throughout the visible spectrum. We locked also permanently such colloidal crystals by cross-linking of poly(2-hydroxyethyl methacrylate) (PHEMA) brush phases with glutaraldehyde. The peak wavelength (lambda(max)) in the reflection spectra agreed well with the bandgap position for light incident on the (1 1 1) face of face-centered cubic (fcc) lattice according to Bragg's law. (C) 2010 Elsevier Inc. All rights reserved.