This study investigates the mechano-optical properties of chiral nematic liquid crystal (N* LC) elastomers with a uniaxial in-plane helical-axis alignment. We fabricate a freestanding N* LC elastomer by using a recently reported method. N* LC elastomers display anisotropic mechanical properties; elongation parallel to the helical-axis alignment induces greater stretching than elongation perpendicular to the alignment, owing to changes in elastic energy associated with the helical pitch. Moreover, the elastomers exhibit robust mechano-optical properties with strain-dependent variations in the diffraction angle. In contrast to conventional achiral LC elastomers, the diffraction properties of the N* LC elastomers remain intact even under large strains (approximate to 200%). Importantly, the elastomers exhibit polarization-specific functionalities. Under linearly polarized light inclined at 0 degrees or 90 degrees to the helical axis or circularly polarized light, the polarization plane of the diffracted light is rotated by 90 degrees or converted into circularly polarized light with the opposite handedness. These results indicate that the molecular alignment within the elastomer is well maintained under applied strain and contributes to its unique optical properties. The versatility of these materials highlights their potential for advanced applications such as optical sensors, flexible diffraction gratings, and novel polarization-specific optical components.

Sensing technologies capable of quantitatively measuring mechanical stress are essential in fields such as robotics. Here, we present a material that enables real-Time, electronic-free stress sensing through structural color changes. The material is a multilayered film incorporating chiral-nematic liquid crystalline elastomers (N∗ LCEs) which respond to mechanical deformation such as elongation and compression by altering their reflection color. N∗ LCEs exhibit both optical properties derived from their helical molecular organization and elasticity typical of rubber-like materials. Our system differs from conventional LCEs in that it features a multilayer architecture designed to independently control the relaxation dynamics of optical responses without requiring chemical modification. This design achieves both rapid response and reversibility which are vital for practical applications. For both elongation and compression, the applied strain can be quantitatively evaluated through reflection color shift. These findings highlight the material's potential for use in next-generation mechanoresponsive devices, including wearable sensors, structural health monitors, and intelligent robotic skins. © COPYRIGHT SPIE.

We synthesised Au(i) complex C6 with a non-conjugated cyclohexyl isocyanide ligand. Despite lacking π-conjugation, C6 crystals show intense yellow RTP at 620 nm, surpassing π-conjugated P6. Efficient emission arises from aurophilic-interaction-driven aggregation and excited-state Au⋯Au shortening, highlighting a strategy to enhance metallophilic interactions in heavy-metal aggregation-induced emitters. This journal is © The Royal Society of Chemistry, 2025