Template-Based Growth of Oxide Nanorod Arrays by Centrifugation

This paper reports template-based growth of nanorod arrays by combination of sol–gel processing and centrifugation. The technical concept is simple and straightforward; centrifugation force drives the sol nanoclusters into the pores of the template, filling the pores completely to form nanorods. However, simulation reveals the formation of nanorods inside pores is more complex; centrifugation force is insufficient to overcome the energy barrier that prevents agglomeration of two nanoclusters. Thermal fluctuation and solvent evaporation upon drying are considered to be the forces leading to the eventual agglomeration of concentrated nanoclusters inside template pores. Dense nanorods with 200 nm diameter and 10 m length were readily obtained from polymeric SiO₂, colloidal SiO₂, TiO₂ and PZT sols after heat treatment.