Preparation of erasable mechanochromic blue phase liquid crystal polymer films based on Michael addition reaction

Elastically deformable self-assembled three-dimensional nanomaterial blue phase liquid crystals (BPLCs) represent a prime target for stimulus-responsive materials. However, there has been little research on the mechanochromic ability of BPLCs, especially in terms of pressure-induced colour changes. In this study, we fabricate erasable mechanochromic blue phase liquid crystal polymer (BPLCP) films via thiol-ene Michael addition reaction. The Michael addition reaction can significantly shorten the preparation time, improve the colour change effect and enhance the mechanical properties of the film. The variation patterns of reflective peaks in thin films under different pressures were investigated, and the effects of distinct components on reflective wavelength shifts, mechanical properties, and recovery time were analysed. This film enables the creation of reconfigurable erasable patterns through applied pressure, with printed patterns retaining stability for over 10 days. Meanwhile, the pattern can be erased by heating and can be cycled multiple times. This study provides new insights into customisable stimulus-responsive 3D photonic nanostructured materials, advancing their applications in sensing, displays, and anti-counterfeiting technologies.