Yip, Wai Tak2019-04-272019-04-272010https://hdl.handle.net/11244/319217As a widely-explored subject for numerous applications, silica sol-gel has attractedthe attention of our group for sensor development. This study focused on pore surfacemodification of two different types of silica sol-gel by post-grafting method, andconstruction of stable silica hydrogel-like thin films. By monitoring the mobility andphotostability of rhodamine 6G (R6G) molecules in silica alcogel thin films throughsingle molecule spectroscopy (SMS), the guest-host interactions altered bypost-synthesis grafting were examined. Similar post-grafting method was then appliedto highly hydrated silica hydrogel monoliths; more efficient surface modification wasexpected, because larger pore sizes in hydrogel provide higher accessibility oforganosilane reagents. During the study of post-grafting on alcogel thin film, a newapproach to produce stable silica hydrogel-like thin films was discovered. A lot of efforthas been made to improve the reproducibility of sample preparation, and the guestloading capacity of silica hydrogel-like thin films. A prototype silica hydrogel-like thinfilm pH sensor was also constructed and tested.12Understanding how guest-host interactions can be affected by silane modificationsis critical to sensor development. It helps tailoring the local environments inside silicasol-gel matrix, so that higher guest loading, longer shelf-life, higher sensitivity andfaster response of silica gel based sensors could be achieved. Stable silica hydrogel-likethin film with a thickness only around 200 nm, which to the best of our knowledge hasnever been accomplished before, is expected to be a better substrate for sensing devicesthat demand faster response than thick monoliths208 pagesapplication.pdfColloidsSilica gelCeramic materialstext