Department of Medical Oncology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, 310003, P. R. China.
College of Energy Engineering and State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, Zhejiang Province, 310027, P. R. China.
Adv Mater. 2021 Mar;33(10):e2006361. doi: 10.1002/adma.202006361. Epub 2021 Feb 1.
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.
自然界中的生物能够根据环境刺激对其颜色、形状和形态进行惊人的控制，以实现伪装、通讯或繁殖的目的。受章鱼通过色素细胞的伸缩来实现伪装的启发，扁球胆甾相液晶微滴分散在聚合物基质中，充当色素细胞的角色，并由于其周期性螺旋结构的选择布拉格反射而呈现结构色。通过手性掺杂剂浓度或温度改变螺旋周期，可以调节 3D 打印仿生系统的颜色。当扁球液晶微滴加热到各向同性时，不透明的有色仿生系统变得透明无色。同时，各向同性液晶微滴趋于变成球形，导致沿膜平面的体积收缩和垂直方向的体积膨胀。内部应变与各向同性扁球液晶微滴的梯度分布相结合，导致相应的形状变化。仿生章鱼的伪装和仿生花朵的绽放都表现出协同的颜色和形状响应，这启发了功能材料和智能设备的设计。
