Stable synthesis of high aspect ratio submicron SiO2 wires by wet chemical methods

Abstract

This study presents a method for the production of SiO₂ wires in a system composed of isopropanol, polyvinylpyrrolidone, ammonia and sodium citrate. The typical wires were mildly curved with an average diameter of 500 nm and an aspect ratio up to 60 or more. A 50-fold expansion of this process still gave stable wires with a yield of about 86 %. Monitoring the sodium levels along the SiO₂ wires revealed that sodium was present in different parts of the wires. Based on this phenomenon, we propose a growth mechanism for SiO₂ wires. The present system produces SiO₂ wires more stably and efficiently than the previously reported n-pentanol-PVP-ammonia-sodium citrate method, while significantly reducing both the amount of PVP and the preparation time.