A Wave‐Driven Piezoelectrical Film for Interfacial Steam Generation: Beyond the Limitation of Hydrogel

Abstract

Solar interfacial vapor generation based on low evaporation energy requirements is an effective technology to speed up water purification under natural sunlight, offering great potential to alleviate the current global water crisis. The external electric field and hydrogel are two independent methods enabling low‐energy water evaporation. However, the complicated external equipment for generating an electric field and the restricted activation area of hydrogels significantly limit their practical application in steam generation. Thus, a piezoelectric fiber membrane is embedded into a highly hydratable light‐absorbing poly(vinyl alcohol) (PVA) hydrogel for synergistic water activation. The integrated evaporator is capable of continuously converting the wave energy reserved in the ocean into electrical energy, activating the water in the hydrogel. It is found that the activation effect leads to an improvement of over 23% compared to a non‐piezoelectric hydrogel evaporator. This work provides an evaporation prototype based on the synergistic water activation of wave‐triggered electricity and highly hydratable hydrogel.

Recent Progress on Structure Manipulation of Poly(vinylidene fluoride)‐Based Ferroelectric Polymers for Enhanced Piezoelectricity and Applications

“…Reproduced with permission. [266] Copyright 2022, Wiley-VCH GmbH. mechanical vibration of electrospun PVDF piezoelectric films through topology optimization design, Lan et al prepared piezoelectric films with similar dimensions but different topological patterns as textile acoustic sensors (TAS).…”

“…Meng et al prepared highly anisotropic P(VDF-TrFE) fiber membranes by electrospinning and embedded them into a highly hydratable light-absorbing PVA hydrogel to create a solar-steam generator. [266] This generator could collect the kinetic energy of ocean waves and coactivate water to accelerate the rate of water evaporation (Figure 12i), providing a more practical solution for efficient and low-energy solar-powered water purification. In recent years, new applications for PVDF-based piezoelectric materials have emerged.…”

Recent Progress on Hydrogel-Based Piezoelectric Devices for Biomedical Applications

“…Hydrogel patches with self-powered ultrasonic transducers can also be adhered to human organs for ultrasound detection, and in the in vitro phase, the ultrasound response can be tested by using ultrasound to stimulate transducers [ 100 , 101 ]. In the field of water purification, piezoelectric materials can be driven by water waves to produce deformation, which in turn generates electrical energy to accelerate the evaporation of water from hydrogels [ 102 ]. Ultrasound stimulation of biological implants can supply power to the implant in all directions, thus avoiding the use of batteries and facilitating a more flexible design of the device [ 103 , 104 ].…”

“…To improve the water purification efficiency, Meng et al proposed a method that uses water waves to drive the PVDF-TrFE piezoelectric layer to generate electrical energy and thus activate the water in the PVA hydrogel, which provides a low enthalpy of evaporation (1.077 kJ/g) and a high vapor-production rate (2.702 kg/m 2 h). The graphene oxide in the hydrogel can also absorb sunlight for photothermal conversion after reduction, and these two synergistic effects provide a prototype for water evaporation [ 102 ].…”

Flexible Sponge‐Based Nanogenerator for Energy Harvesting from Land and Water Transportation

“…The real wave monitoring video shows in Video S6, Supporting Information. [36] Figure 6f shows a concept that the sponge with high sensitivity and tolerance suffering from force and long service life can be arranged in large arrays as a sensor on the load-bearing piles for coastal and offshore platforms, which can monitor the wave slapping force and make predictions to anticipate the occurrence of dangerous situations. To showcase the advantage of sponge TENG, many designs were investigated and compared, as shown in Table S6, Supporting Information.…”