Preparation Of Gel Photonic Crystal Materials And Its Application In Solvent Field

Colloidal photonic crystals are composed of monodisperse sub-micron or micron-sized colloidal particles that are spatially ordered over long distances to form a periodic structure,and have attracted widespread interest from scholars for their unique optical properties.As research into such materials continues,scholars expect to prepare multifunctional and integrated high-performance composite materials based on colloidal photonic crystal materials,providing theoretical and technical support for the development and application of a new generation of optoelectronic devices,sensors,display technologies,etc.In the preparation of photonic crystals,the self-assembly technique has been favoured by more scholars for its simple operation process and low cost,and it has led to techniques such as lifting and pulling.gravity sedimentation and vertical/slope solvent evaporation.However,the self-assembly method is only applicable to monodisperse microspheres and requires strict control of process parameters such as particle size,suspension concentration and type of dispersion medium during preparation.In addition,the method cannot regulate the number of layers deposited on the substrate,the preparation cycle is long,and the bonding between the self-assembled photonic crystal microspheres is mainly dependent on the weak electrostatic interaction between the microspheres,which makes them more prone to breakage.It is a great challenge to explore practical means and methods for the preparation of colloidal photonic crystals from the specific functional and application needs of the target material and to provide a practical pathway for the preparation and application of colloidal photonic crystal materials.Based on this,this paper is oriented towards the assembly of colloidal particles and the preparation of multi-functional nanomaterials,with the starting point of solving the problems of complex photonic crystal preparation process,long cycle time,easy destruction of structural colour and short life span,aiming to achieve multi-functionalization of colloidal particles by various means.The main research content is as follows:(1)Synthesis of monodisperse colloidal particles and study of their assembly behaviour and optical properties:Monodisperse inorganic silica(SiO2)colloidal particles were synthesized by the sol-gel seed method,and the effect of the initial monomer concentration on the particle size of SiO2 colloidal particles was investigated,and colloidal particles of different particle sizes were successfully prepared.Using the vertical deposition self-assembly method and the synthesized monodisperse SiO2 colloidal particles as the basic building blocks,the process conditions for the preparation of colloidal photonic crystal films were investigated and optimized,and colloidal photonic crystal films with different photonic band gaps were formed.The wavelength coverage of the structured colour-reflected light covers most of the visible region,laying the foundation and practical experience for further exploration of the assembly principles and techniques of colloidal photonic crystals.(2)Rapid preparation of agar-based photonic crystal materials and study of their optical properties:The principle of osmosis was adopted to achieve the preparation of agar-based colloidal photonic crystal films using agar molecules as the loading matrix,and the evolution of the preparation process concerning the optical properties was explored.The effects of solvent concentration,monomer ratio and binder on the properties of the target materials were investigated;Fourier infrared spectroscopy and scanning electron microscopy were used to structurally characterise and evaluate the properties of the resulting agar-based photonic crystal materials.The application of agar-based photonic crystal materials in sensing applications such as solvent detection and humidity detection is extended.(3)Preparation of gelatin-based photonic crystal materials and study of their optical properties:The gelatine molecules were added to a restricted domain space composed of silica and air using osmosis,and after a short period of drying at constant temperature,Gelatin-based photonic crystal films were formed.The effects of different solvent concentrations on their properties were investigated.The optical properties and microstructure were analysed using characterisation techniques such as Fourier infrared spectroscopy and scanning electron microscopy.In conjunction with their stability and structural colour properties,the principles of structural colour change and the corresponding reflectance spectra of Gelatin-based photonic crystal materials in different humidity and different solvents are investigated,and their service life and response characteristics in the sensing field are explored.