Study of Silica Sol-Gel Materials for Sensor Development
Abstract
As a widely-explored subject for numerous applications, silica sol-gel has attracted the attention of our group for sensor development. This study focused on pore surface modification of two different types of silica sol-gel by post-grafting method, and construction of stable silica hydrogel-like thin films. By monitoring the mobility and photostability of rhodamine 6G (R6G) molecules in silica alcogel thin films through single molecule spectroscopy (SMS), the guest-host interactions altered by post-synthesis grafting were examined. Similar post-grafting method was then applied to highly hydrated silica hydrogel monoliths; more efficient surface modification was expected, because larger pore sizes in hydrogel provide higher accessibility of organosilane reagents. During the study of post-grafting on alcogel thin film, a new approach to produce stable silica hydrogel-like thin films was discovered. A lot of effort has been made to improve the reproducibility of sample preparation, and the guest loading capacity of silica hydrogel-like thin films. A prototype silica hydrogel-like thin film pH sensor was also constructed and tested. 12 Understanding how guest-host interactions can be affected by silane modifications is critical to sensor development. It helps tailoring the local environments inside silica sol-gel matrix, so that higher guest loading, longer shelf-life, higher sensitivity and faster response of silica gel based sensors could be achieved. Stable silica hydrogel-like thin film with a thickness only around 200 nm, which to the best of our knowledge has never been accomplished before, is expected to be a better substrate for sensing devices that demand faster response than thick monoliths
Collections
- OU - Dissertations [9305]