One-dimensional assembly of silica nanospheres mediated by block copolymer in liquid phase

(Figure Presented) Colloidal silica spheres and their assembly processes are encountered in nature and numerous technological applications. We report here a novel and facile method to prepare highly anisotropic one-dimensional (1D) arrays of silica nanospheres (SNSs) in the liquid phase. Uniform-sized SNSs ca. 15 nm in size assemble into a 1D chain-like structure in the presence of a commercially available block copolymer. The 1D assembly in the liquid phase is evident from Cryo-TEM observations and time-dependent turbidity measurement of the suspension. The mode of the assembly has been systematically controlled by the concentration of the block copolymer, pH of the suspension, and the concentration of a salt added to the system. These results suggest the importance of the balance between electrostatic repulsion and block copolymer-mediated attractive interaction that are operative between particles in the formation of 1D array.