A High-Performance Passive Radiative Cooling Metafabric with Janus Wettability and Thermal Conduction.

With the development of industry and global warming, passive radiative cooling textiles have recently drawn great interest owing to saving energy consumption and preventing heat-related illnesses. Nevertheless, existing cooling textiles often lack efficient sweat management capacity and wearable comfort under many practical conditions. Herein, a hierarchical cooling metafabric that integrates passive radiation, thermal conduction, sweat evaporation, and excellent wearable comfort is reported through an electrospinning strategy. The metafabric presents excellent solar reflectivity (99.7%, 0.3-2.5 µm) and selective infrared radiation (92.4%, 8-13 µm), given that the unique optical nature of materials and wettability gradient/micro-nano hierarchical structure design. The strong moisture-wicking effect (water vapor transmission (WVT) of 2985 g m-2 d-1 and directional water transport index (R) of 1029.8%) and high heat-conduction capacity can synergistically enhance the radiative cooling efficiency of the metafabric. The outdoor experiment reveals that the metafabric can obtain cooling temperatures of 13.8 °C and 19.3 °C in the dry and sweating state, respectively. Meanwhile, the metafabric saves ≈19.3% of annual energy consumption compared with the buildings with HAVC systems in Shanghai. The metafabric also demonstrates desirable breathability, mechanical strength, and washability. The cost-effective and high-performance metafabric may offer a novel avenue for developing next-generation personal cooling textiles.

Asymmetric Multienergy-Coupled Radiative Warming Textiles for Personal Thermal-Moisture Management.

In order to address the requirements for warmth and energy conservation in cold climates, the development of personal thermal management textiles that regulate local human thermal comfort has emerged as a promising solution in recent times. Nevertheless, existing warming textile strategies often rely on a singular energy source, exhibit inadequate air/moisture permeability, and lack adaptability to dynamic and intricate climate variations. Herein, a novel multienergy-coupled radiative warming Janus textile has been effectively designed and fabricated via screen printing and foam finishing. Taking advantage of the synergistic effects of directional water transport capability of polyester-covered cotton (with a directional water-transport index of R = 577.5%), high mid-infrared radiant reflection (at 60%), electrothermal conversion of copper coating (with a sheet resistance of 0.01 Ω sq-1), and strong solar absorption of the nanoporous structure TA@APTES@Fe(III)@CNT (TAFC) coating (at 98.5%), the Janus fabric exhibits exceptional performance in expelling out one-way sweat/moisture (R = 329.3%) and solar heating (86.9 °C)/Joule heating (226.4 °C at 3.0 V)/heat retention (2.4 °C higher than that of cotton fabric). Furthermore, the fabric is also provided with exceptional mechanical, washing, flame-retardant, and antibacterial performance. This research holds the potential to revolutionize the development and production of warming textiles by incorporating desirable sweat/moisture permeability and multienergy-coupled heating.

Thermodynamically Induced Interfacial Condensation for Efficient Fog Harvesting.

Fog harvesting is a sustainable approach to dealing with the global freshwater crisis. A range of strategies in microstructure design and wettability remodeling for fog management are clearly explained. However, the influence of thermodynamic endothermic and exothermic processes on fog harvesting is rarely explored. Here, a thermodynamically induced interfacial condensation-enhanced fog-harvesting fabric (AWF-6) is developed that also incorporates asymmetric geometry and surface chemistry. By coupling the high thermal conductivity interface supported by boron nitride nanosheets (BNNS), the Laplace pressure difference generated by nanoneedles, and the wettability gradient constructed by stearic acid (STA), the fabric achieves a water collection rate (WCR) of 1538.4 mg h cm-2 , which is the maximum value in state-of-the-art cotton-based fog harvesting devices (FHDs). Furthermore, the potential application of AWF-6 in agricultural irrigation is demonstrated. This study shows a thermodynamic proposal for building next-generation fibrous FHDs.

Construction of a Reciprocal-Supporting Phenol-amine@CuNW Network for Antisedimentation Conductive Ink.

Homogeneously dispersed copper nanowire (CuNW) materials are the basis for practical applications in many types of electronic devices. At present, the dispersion of CuNWs in water is achieved through polymeric spatial site resistance effects primarily and the electrostatic dispersion mechanism in a few. However, the electrical conductivity of CuNWs could be weakened by the excessive addition of polymers; therefore, it is difficult to maintain a stable dispersion enduringly for surface charge modifiers. Based on the coagulation mechanism of colloids, a novel antisedimentation mechanism is refined by this work. Directed by this mechanism, a stable reciprocal-supporting antisedimentation conductive CuNW ink was achieved enduringly and a uniform conductive coating (1.81-5.65 Ω·sq-1) was successfully manufactured. The tannic acid-polyethylene imine (TA-PEI) could support copper nanowires to maintain a stable height of 61.4% after 15 days best, while CuNWs in other systems would settle completely in one day. Meanwhile, the TA-PEI composite cluster antisedimentation network not only provided massive spatial potential resistance for CuNWs but also modified the surface charge of CuNWs. CuNWs were dispersed stably in this phenol-amine@CuNW network. Furthermore, the CuNWs were crosslinked more tightly with each other relying on the vigorous adhesive properties of TA-PEI. With this antisedimentation mechanism and simple treatment process, CuNW ink will be utilized in more applications.

Asymmetrical Emissivity and Wettability in Stitching Treble Weave Metafabric for Synchronous Personal Thermal-Moisture Management.

Developing textiles with passive thermal management is an effective strategy to maintain the human body healthy as well as decrease energy consumption. Personal thermal management (PTM) textiles with engineered constituent element and fabric structure have been developed, however the comfortability and robustness of these textiles remains a challenge due to the complexity of passive thermal-moisture management. Here a metafabric with asymmetrical stitching treble weave based on woven structure design and yarn functionalization is developed, in which the thermal radiation regulation and moisture-wicking can be achieved simultaneously throughout the dual-mode metafabric due to its optically regulated property, multi-branched through-porous structure and surface wetting difference. With simply flipping, the metafabric enables high solar reflectivity (87.6%) and IR emissivity (94%) in the cooling mode, and a low IR emissivity of 41.3% in the heating mode. When overheating and sweating, the cooling capacity reaches to ≈9 °C owing to the synergistic effect of radiation and evaporation. Moreover, the tensile strengths of the metafabric are 46.18 MPa (warp direction) and 37.59 MPa (weft direction), respectively. This work provides a facile strategy to fabricate multi-functional integrated metafabrics with much flexibility and thus has great potential for thermal management applications and sustainable energy.