Study On The Technology And Performance Of ZnO/PANI Humidity Sensor Based On Electrochemical Deposition

Humidity sensing materials are widely used in aerospace,industrial and agricultural production,and people's daily life.As a common humidity sensing material,zinc oxide has the advantages of good crystallinity and easy synthesis.However,the traditional zinc oxide materials have low sensitivity and poor environmental stability,which restricts the application of humidity sensing materials.In this paper,a kind of zinc oxide/polyaniline humidity sensitive film was prepared by electrochemical deposition of Polyaniline and zinc oxide with good conductivity and environmental stability.The main work is as follows:Based on the diffusion limited aggregation model and fractal theory,the standard DLA(diffusion limited aggregation)model was modified to simulate the process of electrodeposition of polyaniline,and the electrodeposition parameters of polyaniline with different morphologies were obtained.The simulation results show that the current density has a great influence on the morphology of polyaniline.At low current density,the growth of polyaniline is more dispersed and has more branches;at high current density,the growth of polyaniline is relatively dense,and part of polyaniline agglomerates to form a block morphology.Combined with the simulation results,the method of periodic electrodeposition of polyaniline is proposed,which provides a theoretical basis for the subsequent process research.Based on Faraday's law,the morphology of polyaniline prepared by electrodeposition process was optimized.The morphology of polyaniline was controlled by changing the electric quantity,electroplating time and current density in the process of electrodeposition.Finally,polyaniline with fibrous structure was obtained,and ZnO particles could be loaded on the surface of polyaniline.SEM results show that the diameter range of polyaniline fiber is about 700 nm?1 ?m.Compared with other morphologies,the fiber-like polyaniline composite film has the best performance.Its electrochemical active area is 2.4465×10-2 cm2,and the specificThe humidity sensing properties of ZnO/polyaniline humidity sensing materials were tested in different humidity environments.The results show that compared with other humidity sensing materials,the fiber-shaped polyaniline humidity sensing material has better sensitivity,and the maximum sensitivity can reach 0.77.Based on the first principles of density functional theory,the adsorption process of water molecules on ZnO was simulated.The results show that the adsorption energy of(001)crystal surface of ZnO is-0.69 eV.