A NEW METHOD TO PREPARE UNIFORM PARTICLES - PRECIPITATION FROM LYOTROPIC LIQUID-CRYSTALS

Basic copper sulfate particles of uniform size and shape were prepared at room temperature by precipitation from a lyotropic liquid crystal of water and Tween 80, a nonionic surfactant. The size (< 2.5-mu-m) of the particles depended on the pH of the aqueous copper salt solution and the precipitation time. The formation of the basic precipitates at room temperature was due to the presence of polyethylene oxide chains in the aqueous layers, while the narrow size distribution was due to immobilization of particle nuclei by the rigidity of the liquid crystal.