Synthesis and Characterization of Plate-Like Titanate/Cobalt Blue Pigment Composites

Abstract

Plate-like titanate/cobalt blue pigment composite was successfully synthesized by mixing cobalt blue ( CoAl 2 O 4) pigment nanoparticles with plate-like lepidocrocite-type potassium lithium titanate ( K 0.8 Li 0.27 Ti 1.73 O 4, PLT) microparticles in water in order to improve the comfort and covering ability when applied on skin as cosmetics. PLT was synthesized by KCl flux method at 1000°C for 5 h using K 2 CO 3, Li 2 CO 3 and TiO 2 as starting materials, while CoAl 2 O 4 nanoparticle was synthesized by mixing Co ( NO 3)2 ⋅ 6 H 2 O and Al ( NO 3)3 ⋅ 9 H 2 O with the molar ratio of Co:Al 1:6 at pH 9 followed by calcination at 1000°C for 1 h. The morphology of the PLT/ CoAl 2 O 4 composite strongly depended on the solution pH. Since in a low pH solution, the surface of PLT was negatively charged, while that of cobalt blue was positively charged, CoAl 2 O 4 nanoparticles were homogenously coated on the surface of PLT by electrostatic attraction force. PLT/ CoAl 2 O 4 composites obtained showed nice feeling, high flickering pearlescent, excellent UV-shielding characteristic and novel blue color.