Rapid and Reversible Tuning of Structural Color of a Hydrogel over the Entire Visible Spectrum by Mechanical Stimulation

In this work, we report a rubberlike elastic hydrogel containing microdomains of bilayers periodically stacked into the polymer network that satisfy the Bragg’s law of diffraction. The rubberlike elastic hydrogel has been synthesized by applying double network principle into a viscoelastic hydrogel containing single-domain macroscopic lamellar bilayer. The hydrogel is able to tune the magnificent structural color reversibly over the entire wavelength range of visible spectrum as fast as the uniaxial tensile stretching and compressive deformation are applied and released. Owing to the strength, softness, and rubberlike elastic deformability, the tunable hydrogel can be used extensively to design a new class of soft tactile sensor as an advanced stress sensor that is able to detect a local deformation of a complicated force field.本研究报道了一种类橡胶弹性水凝胶，其聚合物网络中嵌入了周期性堆叠的双层微区，该微区符合布拉格衍射定律（Bragg's law）。该类橡胶弹性水凝胶通过将双网络（double network）原理应用于含单畴宏观层状双层的粘弹性水凝胶中合成得到。该水凝胶可在可见光光谱的全波长范围内可逆调控绚丽的结构色，响应速度与单轴拉伸、压缩形变的施加与解除同步。凭借其高强度、高柔软性与类橡胶弹性形变能力，这种可调谐水凝胶可被广泛用于构建新型柔性触觉传感器——一种可检测复杂力场局部形变的先进应力传感器。