The characteristics of the directed transport of liquids based on Janus membranes play a crucial role in practical applications in energy, materials, physics, chemistry, medicine, biology, and other fields. Although extensive progress has been made, it is still difficult to realize the accurate controllability of liquid directional transmembrane transport. The current gating strategies for the directed transport of liquids based on Janus membranes still have some limitations: (a) using magnetic fluid may cause contamination due to the addition of new substances and (b) utilizing hydrophobicity/hydrophilicity conversion of titanium dioxide requires a long switching time (over 30 min). Herein, a strategy is proposed to precisely control liquid directional transport by altering the wettability of droplets on Janus films prepared by a femtosecond laser through photothermal effects. Infrared laser irradiation on Janus film coated with CNTs can effectively convert light energy into thermal energy, rapidly increase the surface temperature of Janus film, and change the wettability of the liquid on the film. Liquid transmembrane directional transport can be achieved within a few seconds without contaminating the transported liquid. The proposed gating strategy can enable the application of Janus membranes in various scenarios such as microchemical reactions, biological cell culture, and interface self-propulsion.

中文翻译：

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飞秒激光制备的基于 Janus 膜的光触发液滴门控策略


基于 Janus 膜的液体定向输运特性在能源、材料、物理、化学、医学、生物等领域的实际应用中发挥着至关重要的作用。尽管已经取得了广泛的进展，但仍然难以实现液体定向跨膜传输的准确可控性。目前基于 Janus 膜的液体定向输送门控策略仍然存在一些局限性：（a） 使用磁性流体可能会因添加新物质而造成污染，以及 （b） 利用二氧化钛的疏水/亲水转化需要较长的切换时间（超过 30 分钟）。在此，提出了一种策略，通过光热效应改变飞秒激光制备的 Janus 薄膜上液滴的润湿性，从而精确控制液体定向传输。红外激光照射涂覆有 CNT 的 Janus 薄膜可以有效地将光能转化为热能，迅速提高 Janus 薄膜的表面温度，改变液体在薄膜上的润湿性。可在几秒钟内实现液体跨膜定向运输，而不会污染运输的液体。所提出的门控策略可以使 Janus 膜应用于微化学反应、生物细胞培养和界面自推进等各种场景。