The frictional electrification properties of the interface are closely related to its environment, and usually the atmosphere with high humidity will accelerate the transmission and dissipation of electrostatic charges during the triboelectric process, greatly reducing the application of friction nanogenerators and other devices in energy harvesting and self-powered sensing and detection. In addition, the influence mechanism of ambient humidity on the generation, transmission and electrostatic accumulation of interfacial frictional charges is not clear. How to achieve high-performance output and stable operation of devices in high humidity environment through material selection and design is still an urgent problem to be solved.
The team of researcher Wang Daoai of the State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, designed a polyvinyl alcohol (PVA)-based TENG based on hydrogen bonding enhancement and applied it to the field of medical masks, which solved the problem that the charge of the middle adsorption layer of the mask was dissipated too quickly during the long-term wearing of traditional polypropylene (PP)-based medical masks. Related papers were published in Advanced Functional Materials.
The hydroxyl functional groups rich in PVA-based intermediate adsorption layer materials can spontaneously form hydrogen bonds with exhaled water vapor molecules to fix water molecules, and realize the enhancement of frictional electrification ability under high humidity. At the same time, the excellent charge storage performance of PVA materials can greatly slow down the dissipation rate of charge, and can realize self-charging of masks through simple and easy methods such as patting and friction, and extend their effective service life.
However, the characteristics of pure PVA materials have slow water absorption rate and poor expansion resistance, which limit the mechanical stability and permeability of PVA-based TENG in high humidity environment. To this end, the research team designed and prepared a polyacrylonitrile/polyvinyl alcohol-calcium chloride composite film, which improved the water absorption and expansion resistance, mechanical and mechanical properties and tribological properties of PVA under high humidity. In addition, the TENG device assembled with this material is applied to seawater desalination, and its energy consumption is only 0.19 kWh m-3, which is much lower than that of traditional DC power supply, which provides a feasible and effective method for using blue energy such as wind energy and wave energy to achieve desalination in situ. (Source: Ye Manshan, China Science News)
Related paper information:https://doi.org/10.1002/adfm.202306702
Structural design and micromorphology of PVA-based moisture-resistant and self-charging masks. Photo courtesy of Lanzhou Chemical Institute.