Laminated Cellulose Hybrid Membranes with Triple Thermal Insulation Functions for Personal Thermal Management Application

Wearable textiles with multiple thermal insulation functions would play a significant role in preventing heat loss and improving personal thermoregulation properties. However, the precise control over the wearable materials with integrated insulation properties as well as the mechanical properties and antibacterial properties remains a challenge. Herein, the laminated cellulose hybrid membrane (LCHM) with triple thermal insulation functions was prepared by orderly vacuum filtration of cattail stick cellulose (CSC), nickel-silver coreshell nanowires (Ni@Ag-NWs), and exfoliated boron nitride nanosheets (BNNS) for personal thermal management application. Characterization results showed that the LCHM has a sandwich structure with an inner layer of Ni@Ag-NWs, middle layer of CSC and an outer layer of BNNS. The LCHM exhibited synergistic thermal management properties via infrared radiation insulation, electrical heating, and thermal insulation from the external environment. In this laminated system, the Ni@Ag-NW layer has a low infrared emissivity (10%) and higher conductivity (1.0 x 10(7) S/m), which can achieve dual thermal management by reducing human radiation and electric heating of the metal layer. Moreover, the introduction of BNNS into the cellulose membrane can play the role of thermal insulation from the external environment in spite of instinct insulation properties of cellulose materials. The cellulose fibers with extraordinary flexibility are self-tangled or tangled with other fibers to ensure the mechanical properties of the LCHM. In addition, the LCHM showed remarkable antibacterial activity against Escherichia coli bacteria. The desirable human thermal management properties of a hybrid membrane, which are comparable to the reported wearable materials, together with the advantages of functional integration, easy preparation, and controllable functional structures, make them excellent candidates for wearable applications.