Flexible/foldable,
self-supporting, porous, and wearable bifunctional
fabrics for sunlight heating and phase change temperature control
are designed and constructed for wearable thermal management. In this
study, coaxial fibers with polyvinylidene fluoride polymer solution
uniformly doped with Cu7S4 as sheath and n-eicosane as core components are fabricated by electrospinning
technology. Remarkably, based on the fast solar-to-thermal conversion
of the photothermal conversion material, the as-obtained fabric provides
sunlight heating for an extra warmth of 25 °C within 1.5 min.
Besides, active temperature control via fabric internal phase transformation
reduces the daily temperature fluctuations, which is superior to that
of the normal and traditional cotton fiber. Impressively, the present
bifunctional fabric possesses both better thermal comfortability,
including breathability, sweat wicking, and stain resistance, and
high durability against wash and soak over 120 h, suggesting its great
potential in wearable technologies for thermal regulation.