Distillation membranes with hydrophobic surfaces and defined pores are considered a promising solution for seawater desalination. Most existing distillation membranes exhibit three-dimensional (3D) stacking bulk structures, where the zigzag water-repellent channels often lead to limited permeability and high energy costs. Here, we created two-dimensional nanowebs directly from the polymer/sol solution to construct dual-asymmetric Janus membranes. By tailoring the phase separation rate, the polymer phase evolved into continuous hydrophilic webs in situ weld on the microporous hydrophobic layer. The webs possess true-nanoscale architectures (internal fiber diameter of ∼20 nm, pore size of ∼140 nm) with enhanced roughness, serving as a superspreading surface to reach a water contact angle of 0° in 1.7 s. Benefiting from the architecture and wettability dual asymmetries, the obtained Janus membrane shows high-efficiency desalination performance (salt rejection >99%, flux of 11 kg m^–2 h^–1, and energy efficiency of 79%) with a thickness of 6.7 μm. Such a fascinating nanofibrous web-based Janus membrane may inspire the design of advanced liquid separation materials.

中文翻译：

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基于二维纳米网的双不对称 Janus 膜，具有超铺展表面，用于高性能海水淡化


具有疏水表面和明确孔隙的蒸馏膜被认为是海水淡化的一种有前途的解决方案。大多数现有的蒸馏膜都表现出三维 （3D） 堆叠本体结构，其中锯齿形防水通道通常会导致渗透率有限和高能源成本。在这里，我们直接从聚合物/溶胶溶液中创建了二维纳米网，以构建双不对称 Janus 膜。通过调整相分离速率，聚合物相在微孔疏水层上演变成连续的亲水腹板原位焊缝。纤网具有真正的纳米级结构（纤维内径 ∼20 nm，孔径 ∼140 nm），粗糙度更高，可作为超铺展表面，在 1.7 秒内达到 0° 的水接触角。得益于结构和润湿性的双重不对称性，获得的 Janus 膜显示出高效的海水淡化性能（脱盐率 >99%，通量为 11 kg m^–2 h^–1，能源效率为 79%），厚度为 6.7 μm。这种迷人的纳米纤维网式 Janus 膜可能会激发先进液体分离材料的设计灵感。