Biomimetic Janus membrane with spongy channels for directional liquid transport
Xiaoju Kuang, Zhenfang Zhang, Haijun He, Xiaotao Ma, Xu Zhang, Lingfeng Zhu, Honglian Cong, Gaoming Jiang, Seeram Ramakrishna, Pibo Ma
Abstract
Janus fiber membranes enable directional liquid transport (DLT) for oil-water separation and moisture management, yet conventional pore-channel designs offer limited efficiency. Herein, we have developed a groundbreaking Janus nanofiber structure inspired by the structural characteristics of plant leaves, specifically the pore gradient and liquid transport channels within leaves. An innovative intermediate buffer layer composed of a three-dimensional helical nanofiber membrane was introduced to boost porosity and horizontal interconnectivity. A dopamine-controlled regulation mechanism synergistically optimized the pore structure and wettability of this layer. The resulting Janus membrane exhibits a remarkable unidirectional transport index (1250%), a high oil-water separation efficiency (98.92%), and an ultra-high flux (13860.77 L·m⁻²·h⁻¹). Its integration with textiles demonstrates superior moisture and thermal management, confirming its versatility for applications in oil-water separation, industrial wastewater treatment, and high-performance functional garments. Directional liquid transport driven by the asymmetric properties of Janus fiber membranes has been used in oil-water separation and moisture management but showing limited water transport efficiency. Here, the authors optimize the porous channels of directional liquid transport Janus fiber membranes by integrating longitudinal channels with a horizontal network.