Wang Jinpei, Wang Jin, Sheng Zhizhi, Du Ran, Yan Lifeng, Zhang Xuetong
Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China.
Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, P. R. China.
Langmuir. 2021 Nov 16;37(45):13501-13511. doi: 10.1021/acs.langmuir.1c02333. Epub 2021 Nov 5.
Gels are soft functional materials with solid networks and open pores filled with solvents (for wet gels) or air (for aerogels), displaying broad applications in tissue engineering, catalysis, environmental remediation, energy storage, . However, currently known gels feature only a single (either solid-liquid or solid-vapor) interface, largely limiting their application territories. Therefore, it is both fundamentally intriguing and practically significant to develop conceptually new gel materials that possess solid-liquid-vapor multiple interfaces. Herein, we demonstrate a unique solid-liquid-vapor triphase gel, named as aerohydrogel, by gelling of a poly(vinyl alcohol) aqueous solution with glutaraldehyde in the presence of superhydrophobic silica aerogel microparticles. Owing to its continuous solid, liquid, and vapor phases, the resultant aerohydrogel simultaneously displays solid-liquid, solid-vapor, and liquid-vapor interfaces, leading to excellent properties including tunable density (down to 0.43 g·cm), considerable hydrophobicity, and excellent elasticity (compressive ratio of up to 80%). As a proof-of-concept application, the aerohydrogel exhibits a higher evaporative cooling efficiency than its hydrogel counterpart and a better cooling capability than the commercial phase change cooling film, respectively, showing promising performance in cooling various devices. Moreover, the resulting aerohydrogel could be facilely tailored with specific (, magnetic) properties for emerging applications such as solar steam generation. This work extends biphase gel (hydrogel or aerogel) to solid-liquid-vapor triphase gel, as well as provides a promising strategy for designing more aerohydrogels serving as soft functional materials for applications in various emerging fields.
凝胶是一种软功能材料，具有固体网络结构以及充满溶剂（对于水凝胶而言）或空气（对于气凝胶而言）的开放孔隙，在组织工程、催化、环境修复、能量存储等领域有广泛应用。然而，目前已知的凝胶仅具有单一（固 - 液或固 - 气）界面，这在很大程度上限制了它们的应用范围。因此，开发具有固 - 液 - 气多界面的概念全新的凝胶材料，在基础研究方面既有趣又具有实际意义。在此，我们通过在超疏水二氧化硅气凝胶微粒存在下，使聚乙烯醇水溶液与戊二醛发生凝胶化反应，展示了一种独特的固 - 液 - 气三相凝胶，即气 - 水凝胶。由于其连续的固相、液相和气相，所得气 - 水凝胶同时展现出固 - 液、固 - 气和液 - 气界面，从而具备包括可调密度（低至0.43 g·cm）、可观的疏水性和出色的弹性（压缩比高达80%）等优异性能。作为概念验证应用，气 - 水凝胶分别表现出比其水凝胶对应物更高的蒸发冷却效率以及比商业相变冷却膜更好的冷却能力，在冷却各种设备方面显示出良好的性能。此外，所得气 - 水凝胶可以很容易地定制具有特定（如磁性）性质，以用于诸如太阳能蒸汽产生等新兴应用。这项工作将双相凝胶（水凝胶或气凝胶）扩展到固 - 液 - 气三相凝胶，同时也为设计更多用作软功能材料以应用于各种新兴领域的气 - 水凝胶提供了一种有前景的策略。
