Marine animals, such as leptocephalus and jellyfish, can sense external stimuli and achieve optical camouflage in the aquatic environment. Fabricating an intelligent soft sensor that can mimic the capabilities of transparent marine animals and function underwater can enable transformative applications in various novel fields. However, previously reported soft sensors struggle to meet the requirements of adhesion, self‐healing ability, optical transparency, and stable conductivity in the aquatic environment. Herein, high‐performance ionogels by virtue of ion–dipole and ion–ion interactions between fluorine‐rich poly(ionic liquid) and ionic liquid are designed. The hydrophobic dynamic viscoelastic networks provide excellent properties for ionogels, including optical transparency, adjustable mechanical properties, underwater self‐healing ability, underwater adhesiveness, conductivity, and 3D printability. A mechanically compliant and visually invisible underwater soft sensor based on ionogel is developed. This sensor can achieve optical camouflage, human‐body‐motion detection, and barrier‐free communication in the aquatic environment. A novel contactless sensing mechanism based on changing the electron transfer pathway is proposed. Several interesting functions, such as detection of water environment changes, recognition of objects, delivery of information, and even identification of human standing posture can be realized. Importantly, the ionogel sensor can avoid fatigue and physical damage in the sensing process.
Underwater electrocardiography (ECG) monitoring, which can monitor cardiac autonomic changes and arrhythmias during diving, is essential for sports management and healthcare. However, it is crucial yet rather challenging to achieve ECG monitoring in an aquatic environment because the interface electrodes may lose their functionality underwater. Here, an ionogel with tailorable mechanical properties is prepared by a facile one-step polymerization and used as water-resistant electrode. The Young's modulus and strain at break of the ionogel can be modulated in the range of 0.22-337 MPa and 349 to >10 000%, respectively. The hydrophobic polymer networks inside the ionogel endow this ionogel with excellent stability, adhesion, and selfhealing ability underwater. The ionic conductivity imparted by the free ionic groups inside the ionogel allows the ionogel to detect and transmit physiological electrical signals. Compared with commercial gel electrodes, this ionogel electrode demonstrates better adhesion ability, conductivity, and stability underwater. The ionogel electrode can collect real-time ECG signals effectively both in the air and underwater, and the data can be used to warn users of the potential risk of a heart attack.
The underwater adhesive with strong, fast and stable adhesion ability has become an urgent requirement for various industrial applications. Herein, a highly transparent ionogel based on fluorine-rich poly(ionic liquid) and...
Solar steam generation, which utilizes sustainable solar energy to produce fresh water, is regarded as a facile and effective way to solve water scarcity issues. However, challenges remain in terms of inefficient water transfer and vapor release, low solar absorption and conversion efficiency, and hydrophobic photothermal materials. Herein, enlightened by water transport through internal microchannels in trees, a tree‐inspired hydrogel (TIH) with vertically aligned channels incorporating MXene as the light absorber is fabricated. Due to the vertically aligned channels, the rapid transfer of water and unobstructed release of steam can be achieved. Furthermore, water state in molecular meshes can be changed by polymer−water interaction, and partial water can be activated to promote water evaporation. Excellent internal photothermal conversion efficiency and hydrophilicity of MXene are also conducive to evaporation. As a result, TIH has achieved an evaporation rate of 2.71 kg m−2 h−1 and energy efficiency of 90.7% under one sun irradiation, which is higher than membrane material and structure‐disordered hydrogel. This design principle, expandable manufacturing route, and excellent performance provide a potential way and design concept for water purification and desalination.
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