Study On The Preparation And Recognition Mechanism Of Molecularly Imprinred Polymers Based On Aggregation-Induced Emission

The research on molecular imprinting technology(MIT)has long been receiving much attention,but issues concerning recognition mechanism and how the impact factors work are still far from clear.It is necessary to thoroughly study the mechanism and influencing factors of molecular imprinting,which is also of great significance to expand the depth and breadth of applications of MIT.Based on the above background,we explored the imprinting and recognition procedures of molecular imprinting polymers(MIP)on functional groups effect and size effect,and studied the adsorption properties of MIP via multiple means including fluorescence and computer simulation.In this work,a series of tetraphenylethene and its derivatives with the phenomenon of aggregation-induced emission(AIE)were designed and selected elaborately as template molecules,and the preparation of AIE-MIP was carried out by bulk polymerization.All the prepared polymers shows a rough surface and a loose porous structure,which favors adsorption and media transportation of substrate molecules.Using the unique luminescence phenomenon of AIE,the process of eluting and rewashing between the imprinted molecule and the polymer is visually traced by the fluorescent "on-off-on" from,which opens up a new approach of "visualization" for studying the mechanism of MIT.Two factors that have major impact on imprinting performance were studied: one is the functional groups of template and the other is the size of template.And we obtained the corresponding rules of molecular imprinting from functional groups effect and size effect.Furthermore,the binding energy and mechanism at the molecular level between templates and polymers were analyzed by density functional theory(DFT)calculations.It turned out that MIP are inclined to combine with the molecules with more effective functional groups or with smaller size.Meanwhile,the more ordered sites and the larger cavities in polymers afforded MIP with better adsorption performance.Imprinting molecules-AIEgens were immobilized in the imprinted cavities after being adsorbed by MIP,and then show the phenomenon of fluorescence.Therefore,the fluorescence intensity can be used as a means to quantify the adsorption capacity of MIP.Correspondingly,a set of quantitative methods of solid fluorescence was established,which provided a new analytical idea for directly measuring the adsorption capacity of MIP.The method broke through the drawbacks of traditional quantitative methods,which obtained the sorption capacity only by indirectly measuring the remaining concentration of substrate molecules in the supernatant.The fluorescence intensity of MIP was measured using a fluorescence spectrophotometer,and the adsorption capacity was obtained according to the obtained standard curve,.Comparing with reconfigure the stadard solution before each exoeriment,like the method of UV-vis,the prepared standard sheets can be reused.Consequently,the quantitative method of fluorescence has the advantages of simple operation,stable and repeatable.In summary,this paper deeply explored the recognition rules of molecular imprinting in terms of functional group effect and functional group effect,and provides theoretical guidance and experimental reference for the specific recognition mechanism of MIP and the design and synthesis of MIP.In addition,a quantitative method of fluorescence has been established,which provides a fresh idea for directly measuring the adsorption capacity of MIP.