Phys.org September 16, 2021
Despite extensive efforts to create colour-changing materials and devices, it is challenging to achieve pixelated structural coloration with broadband spectral shifts in a compact space. An international team of researchers (USA – University of Pennsylvania, South Korea) describes pneumatically inflating thin membranes of main-chain chiral nematic liquid crystalline elastomers that have such properties. By taking advantage of the large elasticity anisotropy and Poisson’s ratio (>0.5) of these materials, they geometrically programed the size and the layout of the encapsulated air channels to achieve colour shifting from near-infrared to ultraviolet wavelengths with less than 20% equi-biaxial transverse strain. Each channel can be individually controlled as a colour ‘pixel’ to match with surroundings, whether periodically or irregularly patterned. These soft materials may find uses in applications such as cryptography, adaptive optics, and soft robotics…read more. TECHNICAL ARTICLE
The researchers’ artificial chromatophores consist of membranes stretched over circular cavities attached to pneumatic pumps…Credit: University of Pennsylvania