Zn2SiO4‐coated microparticles with biologically‐controlled 3D shapes

The synthesis of zinc silicate‐coated microparticles with well‐controlled three‐dimensional (3D) shapes, via chemical modification of the surfaces of diatom microshells, is demonstrated. ZnO nanoparticle‐based coatings were first applied by exposing the microshells to a zinc acetate‐bearing solution and then firing at 700 °C. The ZnO nanoparticles were then allowed to react with the underlying SiO2 micro‐shells at 1050 °C. Thin (submicron), compact, and continuous Zn2SiO4 coatings were generated that conformed to the microshell surfaces. The Zn2SiO4‐coated microparticles retained the starting 3D microshell shape. Given the wide range of microshell shapes available among different species of diatoms (or other SiO2‐forming organisms), this simple and scalable microshell coating method may be used to synthesize functional microparticles with a variety of well‐controlled 3D shapes and tailored silicate chemistries. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)