Integrin-Mimetic Mechanosensory Elastomer with Fluorescence Probe for Monitoring Chain Deformation in Situ

Mechanosensory elastomers attract intense interests in the academic and industrial fields. However, molecular insight of macroscopic properties remains a significant challenge. Herein, we build up a correlation between the microscopic and macroscopic level by designing a mechanosensory elastomer with aggregation-induced emission luminogens (AIEgens) that monitors chain deformation in situ. The key constituents are the mechanosensory units, which are dynamic dimers bonded by ureidopyrimidinone (UPy) groups and tetraphenylethylene (TPE) for the fluorescence signal output. The photoluminescence (PL) technique successfully monitors elastomer chain deformation under external forces. The PL intensity increases linearly at low elongation, in excellent agreement with Hooke's law for ideal chains. Strong deviation from linear PL intensity is measured at high elongation, which can be theoretically described by the Langevin function. A correlation between the microscopic and the macroscopic level is then built.