Polydopamine adhesion of MXenes to cotton fabric for solar thermal and passive radiative heating

Keeping the body temperature relatively constant in a cold environment is critical to maintaining thermal comfort and normal operation of various functions. However, typical heating strategies waste much energy and cannot cope with the complicated and changing environment. Therefore, it is essential to develop a warm textile that can accurately heat the human body in an efficient and energy-saving way. In this work, MXene nanosheets were uniformly deposited on the surface of cotton fabrics via polydopamine (PDA) adhesion to prepare a warm fabric with solar heating and passive radiative heating (PRH). Notably, the obtained MXene-PDA/cotton fabric demonstrated a low mid-infrared emissivity of 19.7% at 7–14 μm and a high absorptivity of 90.7% in the wavelength range 250–2500 nm. Consequently, the MXene-PDA/cotton fabric exhibited effective passive radiative heating performance on the human body, showing a 2.8 °C improvement compared to traditional cotton fabric, and its excellent solar heating capacity could elevate the temperature to 52.5 °C in a simulated light environment of 100 mw/cm². Besides, the MXene-PDA/cotton fabric retained well warmth after machine washing and ultrasonication, and had certain air permeability, wettability, and mechanical properties. This PDA/cotton fabric shows great potential in thermal management, energy-saving heating, and personal precision heating applications.