Multifunctional laminated membranes with adjustable infrared radiation for personal thermal management applications

The laminated membranes that combine adjustable infrared emissivity, sunscreen, antibacterial and breathability are of great significance and challenge for personal comfort thermal management applications in civil, medical and military fields. Herein, the laminated membranes composed of zinc–aluminum layered double hydroxides (LDH)/cotton fiber (CF@Zn–Al LDHs) and zinc oxide nanorods/CF (CF@ZNR) were successfully fabricated by orderly assembly using a vacuum filter pump. The personal thermal management properties, including infrared insulation and heat dissipation, can be controlled via controlling the infrared emissivity of CF@Zn–Al LDHs layer. The antibacterial and ultraviolet resistance properties can be achieved by in-situ growth of ZnO nanorods on CF surface. For the inner layer, the aluminum nano-coating onto the CF (CF@ANC), as the aluminum source for LDH, shows low infrared emissivity (30.2%), which can reduce human body heat radiation to achieve infrared insulation. The Zn–Al LDHs with gradients in morphologies were obtained by in-situ growth on the CF, which exhibit the enhanced infrared emissivity (maximum emissivity of 0.98) to achieve infrared dissipation. For the outer layer, ZnO nanorods arranged vertically on CF (CF@ZNR), which possess high infrared transmittance of about 83.0%, may promote the loss of the human body heat. In addition, the laminated membranes also possess the desired flexibility and breathability. Therefore, the versatility and clever design strategies of laminated membranes have potential application value in the field of personal comfort thermal management.