The Preparation Of Stimuli-responsive Fluorescent Material With Cross-linking-induced-emission And Application

Smart fluorescent materials have been widely applied in biological imaging,luminescent sensing,information transmission,encryption,anti-counterfeiting,etc.,since their fluorescence property can be easily regulated under external stimuli.In recent decades,the design,synthesis,and application of multiple stimuli-responsive fluorescent materials have attracted considerable attention.However,there is a lack of versatile strategy for preparing multi-stimuli responsive fluorescent materials due to their diverse response mechanisms and luminous capacity.This has restricted the further development of smart fluorescent materials and their application.Moreover,the organization and effective combination of different responsive behaviors in one multi-stimuli responsive system remains a significant challenge.In this dissertation,selecting polymethacrylates as template substrate,a series of stimuli-responsive fluorescent materials were developed by modifying the linear polymethacrylates with different stimuli-responsive moieties.Their stimuli-responsive behaviors with AIEgen-contained cross-linker under various stimulations were then investigated and the stimuli-responsive mechanism was studied.As a result,the "stimulus-crosslink-emission" process was proposed and a versatile strategy toward multi-stimuli responsive materials was presented.Based on this kind of materials,adaptable information encryption system and visualized fluorescent adhesive were developed.The main research includes the following three parts:1.A versatile strategy toward stimuli-responsive fluorescent material whose fluorescence property can be regulated on demand is presented.For three different stimulations,three corresponding stimuli-responsive moieties can be introduced into the side groups of linear polymethacrylates precursors and the stimuli-responsive materials were obtained by blending the modified polymethacrylates with AIEgen-contained cross-linker.Under stimuli,modified polymethacrylates can be cross-linked with the cross-linker to form the polymer networks which can restrict the intramolecular rotation of the AIEgens to induce strong emission.2.Based on the research on stimulus-responsive emission behavior,we found that under the corresponding stimulus,both the linear polymer and the cross-linking agent can undergo cross-linking reaction and induce fluorescence enhancement,various stimuli are transferred through the organized "stimuli-crosslink-emission" process to produce strong fluorescence.With this process,various stimuli responsiveness could easily be accomplished by introducing different stimulus-responsive segments.The compatibility of different responses can also be guaranteed.3.The smart fluorescent materials were used as inks to be printed on cellulose paper to prepare a paper-based smart device.Different information encryption systems were constructed by using different stimuli-responsive materials.(1)Different stimuli-responsive polymer inks were combined to prepare an anti-counterfeiting QR pattern.Multiple information encrypted system with high security level was achieved due to the compatibility of different stimuli-responsive behavior.(2)UV and thermal stimulation-responsive polymers have the ability of irreversible cross-linking and reversible cross-linking,respectively.Combining of these two stimuli-responsive moieties in one information encryption system,the encryption and decryption process could be achieved and repeated for many times.4.Visualized fluorescent adhesive was further prepared based on this kind of fluorescent materials.Under external stimuli,the fluorescence intensity of the adhesive can be increased as the increase of the bonding strength,realizing the visualization of the bonding process.