Patent ID: 8906505

Claim:
A composition for colloidal crystals, comprising: core-shell particles (A) each having a core and a shell; and a monomer (B1) having the following formula (1), wherein the core-shell particles (A) constitute 25% to 65% by weight of the composition, and the monomer (B1) constitutes 35% to 75% by weight of the composition, the core has an average particle size in the range of 50 to 900 nm, the shell is formed of a linear polymer composed of at least one of styrene and a monomer (B2) having the following formula (1), one end of the linear polymer is covalently bonded to the core, and the refractive index of the core (n(core)) satisfies the following formulae (2) and (3): wherein R 1 denotes a hydrogen atom or a methyl group, and y is 0 or 1, n (shell)− n (core)≧0.07 (2) wherein n(shell) denotes the refractive index of the shell, and n ( B )− n (core)≧0.07 (3) wherein n(B) denotes the refractive index of the monomer (B1) after curing.