Design,Synthesis And Multi-stimulus Response Performance Of Organic Molecular Cage Membrane Materials

Stimulation responsive materials are a new type of material that integrates self detection,self judgment,and self processing functions.Under the stimulation of environmental factors such as temperature,p H,light,mechanical force,solvents,electromagnetic fields,etc.,certain physical or chemical properties of materials themselves will undergo responsive changes,and have enormous application potential in fields such as sensors,soft robots,coatings,etc.Humidity and volatile organic solvent as a source of stimulation,its content always affects people’s physical and mental health,so the detection of humidity and organic solvent content has become a research hotspot.In addition,combining multiple stimulus responses into the same material is beneficial for expanding its application scenarios.Based on the above research and analysis,the main research content of this paper is as follows:1)We have prepared a new type of sturdy,macroscopic scale,and self-supporting molecular Cage film（Cage film）using a simple solution casting method using pure organic molecular cages for the first time.The obtained Cage film has good mechanical properties and recyclability.After one million bending tests,its stress-strain performance remained basically unchanged,and after cutting healing,its stress-strain performance recovered by 89%,demonstrating excellent mechanical stability and self-healing performance.Then,we used CH₃I solution immersion to methylate the upper surface of the Cage film,establishing a gradient structure of methylation on the cross-section of the membrane.The contact angle test results indicate that the hydrophilicity of the gradient methylated Cage film（P-Cage film）decreases from top to bottom.When the P-Cage film is exposed to organic solvent atmospheres such as water vapor or dichloromethane,the gradient of hydrophilicity and hydrophobicity can cause asymmetric expansion on both sides of the P-Cage film.Therefore,mechanical drive can be immediately triggered by changes in solvent vapor and humidity.In the toluene dichloromethane mixed solvent system,the curvature of the P-Cage film is linearly related to the content of dichloromethane molecules,so it can be used for the detection of trace amounts of dichloromethane.2)In order to integrate multiple stimulus responses such as light,heat,mechanical force,and solvent into organic molecular cage membrane systems,we designed and synthesized a novel multi stimulus responsive molecular cage precursor（DSB-SQ）.It is found that DSB-SQ has the characteristics of aggregation induced luminescence,and can form dimer compounds by[2+2]cycloaddition under the irradiation of simulated light source.In addition,we successfully cultivated two crystal compounds with blue and green fluorescence by utilizing the characteristics of the compound in different solvents with different stacking methods.The mechanism of different fluorescence emissions was analyzed through single crystal data.In addition,the blue fluorescent crystal form can be transformed into a green fluorescent crystal form by heating,accompanied by fluorescence transformation;This fluorescence transition can also be achieved through mechanical grinding stimulation,and reversible fluorescence recovery can be achieved through solvent fumigation.Based on these changes,we designed a PVA/DSB-SQ mixed matrix film that combines thermal,mechanical,solvent,and other multiple stimulus responses for information storage and encryption.Subsequent work will hydrolyze the precursor of this molecular cage and form a molecular cage through condensation reaction with tri（2-aminoethyl）amine.The multi stimulus response performance of molecular cage precursors lays the foundation for the synthesis of multi stimulus responsive molecular cages,and it is expected to integrate multi stimulus response into organic molecular cage membrane systems.