Solar Thermal Textiles for On-Body Radiative Energy Collection Inspired by Polar Animals.

Humans use textiles to maintain thermal homeostasis amidst environmental extremes but known textiles have limited thermal windows. There is evidence that polar-dwelling animals have evolved a different mechanism of thermoregulation by using optical polymer materials to achieve an on-body "greenhouse" effect. Here, we design a bilayer textile to mimic these adaptations. Two ultralightweight fabrics with complementary optical functions, a polypropylene visible-transparent insulator and a nylon visible-absorber-infrared-reflector coated with a conjugated polymer, perform the same putative function as polar bear hair and skin, respectively. While retaining familiar textile qualities, these layers suppress dissipation of body heat and maximize radiative absorption of visible light. Under moderate illumination of 130 W/m2, the textile achieves a heating effect of +10 °C relative to a typical cotton T-shirt which is 30% heavier. Current approaches to personal radiative heating are limited to absorber/reflector layer optimization alone and fail to reproduce the thermoregulation afforded by the absorber-transmitter structure of polar animal pelts. With increasing pressures to adapt to a rapidly changing climate, our work leverages optical polymers to bridge this gap and evolve the basic function of textiles.

High Energy Density, Super-Deformable, Garment-Integrated Microsupercapacitors for Powering Wearable Electronics.

Lightweight energy storage technologies are integral for powering emerging wearable health monitors and smart garments. In-plane, interdigitated microsupercapacitors (MSCs) hold the greatest promise to be integrated into wearable electronics because of their miniaturized footprint, as compared to conventional, multilayered supercapacitors and batteries. Constructing MSCs directly on textiles, while retaining the fabric's pliability and tactile quality, will provide uniquely wearable energy storage systems. However, relative to plastic-backed or paper-based MSCs, garment-integrated MSCs are underreported. The challenge lies in creating electrochemically active fiber electrodes that can be turned into MSCs. We report a facile vapor deposition and sewing sequence to create rugged textile MSCs. Conductive threads are vapor-coated with a stably p-doped conducting polymer film and then sewn onto a stretchy textile to form three-dimensional, compactly aligned electrodes with the electrode dimensions defined by the knit structure of the textile backing. The resulting solid-state device has an especially high areal capacitance and energy density of 80 mF/cm2 and 11 µW h/cm2 with a polymer gel electrolyte, and an energy density of 34 µW h/cm2 with an ionic liquid electrolyte, sufficient to power contemporary iterations of wearable biosensors. These textile MSCs are also super deformable, displaying unchanging electrochemical performance after fully rolling-up the device.