Research On Temperature Sensing Based On Liquid Photonic Crystal

Temperature-responsive photonic crystals can convert temperature changes into visible optical signals,and are a smart response material that does not rely on electricity.Early research work mostly used the method of filling the heat-sensitive gel or liquid crystal matrix in the colloidal crystal voids to construct.The preparation process is complicated,the response temperature range is limited,and the irreversible temperature response is rarely displayed.In view of the above problems,this thesis intends to start with liquid colloidal crystals,using the inherent relationship between its fluid properties and colloidal assembly and optical properties,as well as the reversible assembly and disassembly characteristics,to develop liquid colloidal crystals with reversible thermal response;The synthesis intermediate of solid colloidal crystal,the"colloid crystal-polyethylene glycol"double-layer structure is prepared,and then the thermal response photonic crystal film with memory effect is developed.The specific research content is as follows:In the second chapter of our work,we developed a Si O₂-PCb-Gly three-co mponent liquid photonic crystal with a reversible temperature response.Glycero l is a key component of thermal response.In a low-temperature and high-visco sity solution,the thermal movement of colloidal particles is limited by viscosit y,and an ordered structure and structural color cannot be formed;when the te mperature is higher than a certain temperature,the viscosity of the solution de creases and the colloidal particles assemble and form Liquid colloidal crystals and exhibit structural colors.Under the premise of keeping the content of Si O₂colloidal particles consistent,the volume ratio of glycerol(20%-35%)can be adjusted to achieve different discoloration temperatures(15°C-40°C),thereby ma king a combination of a variety of liquid colloidal crystals The array has a re versible temperature response behavior.Traditional thermally responsive colloida l crystals mainly rely on the change of reflection wavelength,that is,different colors to realize temperature perception,while the material system reported in t his chapter realizes temperature perception through reflection intensity,that is,t he presence or absence of structural color,which is not only innovative,but al so avoids color recognition.The error caused.In the third chapter of the work,we combined the photonic crystal film f ormed by the conversion of the liquid colloidal crystal intermediate with the p olyethylene glycol film to form a double-layer structure,and used the irreversi ble behavior of PEG to penetrate into the colloidal crystal after melting to pre pare a memory type Temperature responsive material.When the ambient tempe rature is lower than the phase transition temperature of PEG,the bilayer film exhibits the structural color of Si O₂ colloidal crystals;when the ambient tempe rature is higher than the phase transition temperature,PEG melts and penetrate s into the colloidal crystals,and the material exhibits Si O₂/PEG(liquid))The structural color of colloidal crystals;even if the temperature returns to a low t emperature,PEG cannot be spontaneously detached from the colloidal crystals,so the material still exhibits a structural color similar to that of Si O₂/PEG(soli d)colloidal crystals at high temperatures.Therefore,through the structural colo r change of the material,it can be discerned whether the ambient temperature is higher than the phase transition temperature of PEG;when PEG with differe nt phase transition temperatures is used to construct a series of double-layer fil m combinations,a temperature memory array can be obtained and the environ ment can be accurately known.The highest temperature experienced.In the fourth chapter of our work,we used hydrophobicized mesoporous s ilica colloidal particles and used liquid photonic crystals composed of them as intermediates to prepare crystalline and amorphous photonic crystal sheets,and studied the photonic crystal thin films.The separation and recognition performa nce of weakly polar chemical substances in reversed-phase thin-layer chromatog raphy.