Aggregation-induced emission active hybrid polymer for detection of peroxides

• Main Author: Yeo, Geradine Li Yee
• Other Authors: Lu Xuehong
• Format: Final Year Project
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/66351
• Institution: Nanyang Technological University

In recent years, terrorist attacks and threats have been increasing around the world on an international scale. Many of these threats involve disguised or improvised explosive devices. As the threats of explosive attacks grow and escalate in magnitude and range, there is an essential need for fast, effective, and accurate detection. Fluorescent sensors are a promising choice as they have a fast response time, good portability, and are highly dependable, all at a relatively low cost. One type of fluorescent sensors displays the phenomenon called aggregation-induced emission (AIE) whereby fluorescence intensity increases upon the formation of aggregates. Currently, there are several of such sensors available in the market for the detection of nitro-explosives. However, almost none of them are designed for the detection of peroxide-explosives. Current studies to discover and understand more about peroxide-explosive sensing detectors have been difficult as many operate on a different mechanism from the well-known principles of AIE. This report shall focus on the synthesis and characterisation of a possible AIE sensor for sensing peroxides. 2,2'-(2,2-diphenylethene-1,1-diyl)dithiophene (M1) is a reported compound that has remarkably low yield and AIE effect. We would like to investigate further on the prospect of employing it as a peroxide sensor. In our experiments, the focus was firstly on monomer and polymer synthesis. Next, we studied the characterisation of their structures via nuclear magnetic resonance (NMR) and their properties. AIE properties were confirmed by dissolving the monomers into solvent mixtures with different THF-H2O volume fractions and tested under ultraviolet (UV) light. Subsequently, detection response and oxidation mechanism were analysed. Relatively good yields of 78.1% for M1 and 51.0% for 2,2'-(2,2-diphenylethene-1,1-diyl)terthiophene (M2) were achieved. The results obtained shows the synthesised compounds have good AIE properties which became enhanced or “turned on” upon the addition of a small amount of hydrogen peroxide (100µL). Moreover, it has a fast response time for M2, making it both a suitable and practical candidate as a peroxide-explosive sensor.