Space cooling occupies a large portion of total building energy consumption, aggravating the energy crisis and restricting human sustainable development, thus an efficient and energy-saving personal cooling technology is in high demand. Recently, thermally conductive fillers, such as boron nitride (BN), are usually enriched to fibrous materials to construct thermal management textiles. However, these fabrication processes are complex and time-consuming, and the resultant materials fail to transmit moisture and resist liquid water. Herein, we develop a facile and scalable methodology to construct highly thermoconductive breathable superhydrophobic nanofibrous membranes to enhance the thermal management of textiles for personal cooling. The strategy causes boron nitride (BN) to be linked with each other along nanofibers, and thus the membranes contain well interpenetrated BN network and remain porous structure simultaneously, improving their thermal conductivity without sacrificing the moisture permeability. In addition, the membranes possess good resistance to water penetration and intriguing superhydrophobicity due to the synergistic effect of the hydrophobic polymeric matrix and improved roughness. As a consequence, the resultant membranes demonstrate outstanding hybrid active-passive cooling performance with ultrahigh in-plane thermal conductivity of 17.9 W m-1 K-1, cross-plane thermal conductivity of 0.29 W m-1 K-1, and high water vapor transmission (WVT) rate of 11.6 kg m-2 day-1, as well as excellent water repellency with water contact angle of 153° and high hydrostatic pressure of 32 kPa, indicating promising utility for the next generation of cooling fabrics.
Keywords: boron nitride nanosheets; electrospinning; personal cooling; superhydrophobicity; thermal conductivity.