3D‐Printed Biomimetic Systems with Synergetic Color and Shape Responses Based on Oblate Cholesteric Liquid Crystal Droplets

TLDR

Living organisms can actively control color, shape, and morphology in response to environmental stimuli for purposes such as camouflage, communication, or reproduction. The authors embed oblate cholesteric liquid crystal droplets in a polymer matrix to mimic pigment cells; by tuning the helical pitch with dopant concentration or temperature, the droplets’ structural color can be adjusted, and heating to the isotropic phase makes the system transparent while the droplets become spherical, inducing volume changes that, together with internal strain and droplet distribution gradients, drive shape transformations. The system successfully demonstrates biomimetic octopus camouflage and flower blooming, exhibiting coordinated color and shape changes that illustrate its potential for functional materials and intelligent devices.

Abstract

Abstract Living organisms in nature have amazing control over their color, shape, and morphology in response to environmental stimuli for camouflage, communication, or reproduction. Inspired by the camouflage of the octopus via the elongation or contraction of its pigment cells, oblate cholesteric liquid crystal droplets are dispersed in a polymer matrix, serving as the role of pigment cells and showing structural color due to selective Bragg reflection by their periodic helical structure. The color of 3D‐printed biomimetic systems can be tuned by changing the helical pitch via the chiral dopant concentration or temperature. When the oblate liquid crystal droplets are heated up to isotropic, the opaque and colored biomimetic systems become transparent and colorless. Meanwhile, the isotropic liquid crystal droplets tend to become spherical, causing volume contraction along the film plane and volume dilation in the perpendicular direction. The internal strain combined with the gradient distribution of the oblate isotropic liquid crystal droplets result in corresponding shape transformations. The camouflage of a biomimetic octopus and the blossom of a biomimetic flower, both of which show synergetic color and shape responses, are demonstrated to inspire the design of functional materials and intelligent devices.