Synthesis Of Multi-stimulus Responsive Conjugated Polymers And Detection Of Carbon Dioxide

Conjugated polymers have been widely used in drug delivery,biological,chemical detection and cell imaging because of their excellent light-harvesting and signal amplification properties.This thesis focuses on the design and preparation of the stimulus-responsive conjugated polymer for the detection of carbon dioxide.The main research contents are as follows:1.A hybrid probe based on guanidinium-pendent oligofluorene?G-OF?and water-soluble conjugated polythio-phene?PTP?has been developed for the turn on detection of CO₂ with low background signal.In the presence of CO₂,the electrostatic repulsion be-tween G-OF and PTP can be effectively enhanced through protonation of the side chains,leading to the disaggregation and thus the“turn-on”fluorescence.The strategy allows for the light-up visible detection of CO₂ with high sensitivity and it is capable of sensitively monitoring the concentration changes of CO₂ in the process of the photosynthesis.The work represents a concept to monitor the photosynthesis based on water-soluble conjugated polymers.2.It is still needed to explore new strategy for rapid in situ detection of CO₂ which is featured as rapid diffusion low concentration and difficulty for detection,Here,a water-soluble,conjugated polymer centered on fluorene and 2,1,3-benzothia-diazole?PFBT?is designed and synthesized for sensing CO₂ in situ with high sensitivity and low background.Upon gaseous CO₂ and dissolved CO₂ is introduced,the weaker electrostatic repulsion and stronger hydrophobic interactions between neighboring PFBT molecules in aqueous solution enhance the interchain contacts of PFBT in relative to that in the absence of CO₂,leading to the intra-molecular energy transfer from the fluorene to the2,1,3-benzothia-diazole?BT?sites and the emission color shift from blue to green,which is sensitively enough to sense the CO₂ in atmospheric air with the content of⁴00 ppm.PFBT is employed to detect the variation of CO₂ concentrations in real time which caused by plants in greenhouse and monitor the photosynthesis and respiration upon cycling day and night in situ.While it is a simple,real-time,visually visible,highly sensitive sensing method for CO₂.