octopus, and so on) are able to produce a wide range of structural colors and photonic patterns to signal and communicate with their own species and others. [4,7] Inspired by nature, scientific efforts have been devoted to develop smart photonic materials which inform the user by changing their structural color. [8][9][10] Mechanochromic photonic materials, which change structural color in response to mechanical stimuli, are attractive for a wide range of applications such as strain mapping, [11,12] stress sensing, [13][14][15][16] anti-counterfeiting, [17][18][19] tunable optical devices, [20,21] and so on. Different materials, such as inorganic, polymeric, and hybrid components have been used to fabricate these mechanochromic photonic devices. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Among these smart materials, cholesteric liquid crystals (CLCs) have garnered significant attention in the

Main-chain cholesteric liquid crystal polymers are a promising candidate for the development of responsive photonic devices due to the combination of selective reflection and soft, elastic properties, but it is difficult to enhance these materials with new kinds of responsiveness due to the inherent lack of mesogenic side groups. Here, a new strategy is showed to obtain a dualresponsive elastic cholesteric polymer material by preparing a semi-interpenetrating network consisting of a cholesteric main-chain polymer and a hygroscopic poly(ampholyte). The material is shown to undergo a redshift of the reflected color upon swelling with water, while the color blueshifts when a strain is applied. Color patterns can be prepared by localized photopolymerization at different temperatures, leading to brightly colored responsive images with high contrast. Due to the elastic nature of the material, it can easily be made into a wearable device, and its application as a multifunctional smart sensor for sweat detection and movement detection is demonstrated. The results show that new responsiveness can be added to main-chain cholesteric polymers by preparation of interpenetrating networks, which can be further extended to develop various kinds of multi-responsive smart materials.

Cholesteric liquid crystals (CLCs) are a significant class of temperature-responsive photonic materials that have the ability to selectively reflect light of a specific wavelength. However, the fabrication of main-chain CLC oligomers with dramatic reflection band variation upon varying the temperatures remains a challenge. Here, a feasible method for improving and controlling the responsiveness of main-chain cholesteric liquid crystal oligomers by the incorporation of a smectic monomer is reported. The smectic monomer strengthens the smectic character of the oligomers and enhances the magnitude of the change of the pitch as a function of temperature upon approaching the cholesteric–smectic phase transition temperature. The central wavelength of the reflection band can be easily modified by mixing in an additional chiral dopant. This promising method will open the door to the preparation of temperature-responsive photonic devices with excellent responsiveness.