A sol–gel approach to self-formation of microtubular structures from metal alkoxide gel films



A technique of preparing microtube shape oxide structures by metal alkoxide gel sheet rolling is presented and discussed. Zr(OBu)4 and Hf(OBu)4 precursors have been used for self-formation of ZrO2 and HfO2 microrolls. The technique involves gelling the surface of concentrated sol, partition of gel film into segments by gel cracking and spontaneous rolling of obtained gel film segments. A phenomenological study of crack evolution in gel films has been conducted. The dependence of the thickness of formed gel film and rolling diameter on hydrolysis extent of metal alkoxide precursor and reaction time is reported.