Leather-Based Multi-Stimuli Responsive Chromisms

Leather is made from the skin of animals and possesses special micro- and nanostructures. Due to the high breathability, durability, strength, elasticity, and softness, leather is widely used in daily life, and is an ideal substrate for future multi-functional wearable smart devices. Herein, two leather-based multi-stimuli responsive chromic devices denoted as UV/thermo/electro chromic device and UV sensor are developed. The UV/thermo/electro chromic device demonstrates instantaneous and reversible chromic responses to applied UV radiation, heat, and electrical voltage with different color changing styles. The pattern design with the assistance of 3D printed molds and the broad selection of dyes/pigments endow the device with high design flexibility and wide applicability. The leather-based UV sensor exhibits a change in color gradient when exposed to UV radiation with different intensities. For more versatile color options, inactive pigments/dyes can be mixed with stimuli-responsive ones in this system. Coating the leather surface with a polyacrylic finishing agent is also conducted, which is a practical and effective method to protect the pigments and/or dyes in the leather, and improves the usability/durability of the devices. This study opens a new avenue to design and develop wearable devices and individual customization/anti-counterfeiting of leather products.