Research On Preparation And Application Of Bionic Superhydrophilic Copper Hydroxide Structure

Superhydrophilic surface has a wide range of applications in self-cleaning,anti-fogging,oil-water separation and other aspects of surface due to its extremely low contact angle and excellent hydrophilic properties.With the increasing functional requirements of superhydrophilic micro-nano materials,the development of its preparation process and the exploration of new applications have become one of the main research directions.The micro-nano structure of copper hydroxide has excellent superhydrophilic properties,and its unique properties and potential applications have become research hotspots.The current difficulties mainly focus on the in-situ preparation of superhydrophilic copper hydroxide micro-nano structures on non-copper substrates,the improvement of related application performance and the exploration of new applications.Therefore,this article has carried out systematic research work on the in-situ preparation process,superwettability and application of the non-copper substrate with superhydrophilic copper hydroxide micro-nano structure.The specific contents are as follows:Focusing on the process parameters in the preparation process of the superhydrophilic copper hydroxide micro-nano structure,the structure and morphology are controlled from the aspects of seed layer,growth time,growth mode,annealing treatment,etc.,to obtain uniform and stable superhydrophilic surface process parameters.Based on the basic principle of the interaction between water droplets and super-hydrophilic surfaces,the wettability,droplet self-diffusion/self-evaporation,droplet self-diffusion/self-evaporation,etc.of the superhydrophilic copper hydroxide surface were studied using test methods such as droplet coating,bending,gluing,and annealing.Properties such as mechanical stability,thermal stability and porosity.The results show that the prepared copper hydroxide nanowires are super-hydrophilic.They remain super-hydrophilic after being bent 100,000 times(R=3 mm),have strong adhesion to the substrate,and have a decomposition temperature of 145?.The surface area is 72.67 m² g^-1.In addition,to solve the problem that the traditional contact angle cannot characterize the difference between different superhydrophilic surfaces,it is proposed to use the average velocity of droplet self-diffusion as the evaluation index.The results show that the surfaces with a growth time of less than 20 min have excellent superhydrophilic properties.Among them,the surface self-diffusion speed of 10 minutes of growth is the largest.Although it remains superhydrophilic after bending,the average self-diffusion speed will decrease due to microcracks.Aiming at the problems that water vapor sensing devices are prone to failure when exposed to water and the response time of copper hydroxide nanowires is too long for water vapor sensing,a quartz crystal microbalance(QCM)is used as a water vapor sensing carrier to prepare grass-like superhydrophilic copper hydroxide in situ on the electrode surface With a micro-nano structure,a self-healing high-sensitivity copper hydroxide QCM humidity sensor was obtained,and the self-made equipment was used to test its moisture-sensing performance and self-healing performance with water.The results show that the copper hydroxide QCM sensor has strong repeatability and high stability,and achieves a sensitivity of up to 85.9 Hz/RH%,and its response recovery time reaches 30 s/1.9 s,which greatly improves the moisture sensing performance of copper hydroxide.The sensor has self-recovery characteristics after being wetted with water,and it still maintains more than 90%of its sensing performance after being wetted 100 times.It can be effectively used in application scenarios such as human finger slip/movement,mouth and nose breathing detection.In addition,first-principles theoretical calculations combined with in-situ dynamic Fourier transform infrared absorption spectrometer characterization(FTIR)experiments revealed the moisture-sensing mechanism of superhydrophilic copper hydroxide.The results show that under the condition of unsaturated water vapor,there is mainly physical adsorption between copper hydroxide and water vapor;when the water vapor is saturated,there is mainly condensation adsorption between copper hydroxide and water vapor.Aiming at the efficiency improvement of the water vapor collection device and the flexibility of the substrate,the natural vein structure is used for reference,and the multi-stage wedge-shaped fractal super-hydrophilic flow channel structure is designed to imitate the vein.The flexible substrate is polyethylene terephthalate(PET)and photolithography is adopted.Sputtering and solution method growth and other processes prepare superhydrophilic copper hydroxide nanowires imitating leaf vein multi-level wedge-shaped fractal flow channels on the surface of the substrate,and use self-made equipment to test its droplet directional movement and water vapor directional collection performance.The results show that the vein-like super-hydrophilic copper hydroxide flow channel can realize the directional self-driving movement and collection of horizontal plane,slope(<7.7°)and curved surface droplets.The four-stage wedge-shaped fractal structure of imitating leaf veins greatly improves the water vapor collection efficiency,which is 1150%higher than that of the unstructured PET surface,and 510%higher than the pure superhydrophilic copper hydroxide surface.For the flexible five-level wedge-shaped structure of imitating leaf veins,the long-distance directional self-driving movement collection of long-distance droplets up to 15 cm is realized,and the area reaches 100 cm².In addition,the use of ANSYS Fluent simulation and high-speed camera in-situ shooting reveals the droplet directional self-driven movement collection mechanism.The results show that there are two types of direct adsorption between the droplet and the water film of the superhydrophilic channel:the direct adsorption of the nanowire and the combined adsorption of the droplet in contact with the water film.When the droplet contacts the water film,under the action of the Laplace pressure difference,the droplet move along a position with a smaller curvature to ensure that the surface energy of the overall water film is minimized.To sum up,this paper systematically studies the preparation process and properties of copper hydroxide micro-nano structure,and faces the application performance improvement issues such as water vapor perception and water vapor collection.It learns from plant structures,uses bionic ideas to design structures and develop devices,and improves the hydroxide,the moisture-sensing and water-collecting performance of copper enhances its practicality,clarifies the water vapor sensing mechanism and the water vapor directional collection mechanism of superhydrophilic copper hydroxide nanowires,and enriches the preparation technology,properties and theories of the bionic structure of copper hydroxide.The research and application of copper and even super-hydrophilic materials provide new ideas and useful references.