The Synthesis And Application Of Environmental Sensitive Fluorophore-Ended Homopolymers

Amphiphilic environmental-sensitive polymers are important smart materials because they can fulfill our requirement of materials by adjusting the changes of environmental immediately. In this work, three kinds of perylene-ended amphiphilic environmental-sensitive homopolymers are synthesized and their structure, performance and self-assembly behavior are investigated. The main contents are as follows:1. Synthesis of the amphiphilic homopolymer using the fluorophore perylene-3,4-dicarboxylic acid monoimides (PMI) as the end-group and the pH-sensitive poly(amino ethyl methacrylate)(PAEMA) as the side-chain. Herein, the fluorophore PMI moiety has a large rigid hydrophobic surface which can provides π-π stacking during self-assembling. Whereas the flexible PAEMA bearing-NH2 behaves as a pH-sensitive hydrophilic moiety. Due to electrostatic repulsion, the self-assemblies of PMI-PAEMA with long polymer chains are pH-switchable. On the other hand, PMI-PAEMA with short polymer chains shows inconspicuous changes with changes in pH.2. Synthesis of the amphiphilic homopolymer using PMI as the end-group and the temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM) as the side-chain, which the Lower Critical Solution Temperature (LCST) is about 32℃. Driven by the π-π stacking of the PMI group, the homopolymer self-assemble into vesicle-type structure and act as temperature-sensitive nanocontainer for drug delivery.3. Synthesis of the amphiphilic homopolymer using N, N-di(propanoic acid)-perylene-3,4,9,10-tetracarboxylic diimide (PDI) as the end-group and the carbon dioxide (CO2)-sensitive poly(2-(Dimethylamino)ethyl methacrylate) (PDMAEMA) as the side-chain. This fluorophore-polymer conjugate exhibits a fluorescent "turn-on" response to the presence of CO2 in aqueous solutions. Upon removal of adsorbed CO2 by N2 degassing, this CO2 chemosensor is completely recoverable. Comparing with the PDI-PDMAEMA 60, star polymer PDI-P(DMAEMA30)8 is more sensitive to the concerntration of CO2, but need more time to quenching by N2 degassing.