COLLOIDAL SINGLE-CRYSTALS OF SILICA SPHERES IN THE PRESENCE OF SIMPLEAND POLY ELECTROLYTES, AND IONIC DETERGENTS

Colloidal single crystals of silica spheres (103 nm in diameter) are f ormed in the presence of various kinds of salts 1 simple electrolytes, i.e., sodium chloride, calcium chloride and lanthanum chloride, 2 pol yelectrolytes such as 3-6 type ionen polymer (polybrene), poly-N-ethyl pyridinium bromide, a copolymer of N-benzyl pyridinium chloride and N- hexadecyl pyridinium bromide, and sodium polyethylene sulfonate, and 3 cationic and anionic detergents, hexadecyltrimethylammonium bromide a nd sodium dodecylsulfate. Shape and size of their single crystals, pha se diagram, and the relationship between the two parameters among the critical concentration of melting, conductance and pH of the crystal-l ike suspensions have been studied. Colloidal single crystals of positi vely charged spheres have been formed in this study by the method of t he charge reversal of spheres through the strong adsorption of cationi c polyelectrolytes onto the anionic silica spheres.