Advancing Dynamic Polymer Mechanochemistry through Molecular Gears

Harnessing mechanical force to modulate material properties and enhance biomechanical functions is essential for advancing smart materials and bioengineering. Polymer mechanochemistry provides an emerging toolkit to unlock unconventional chemical transformations and modulate molecular structures via mechanical force. One of the key challenges is developing innovative force-sensing mechanisms for precise, in situ force detection and quantification. This study addresses this challenge by introducing mDPAC, a mechanosensitive molecular gear with dynamic and sensitive mechanochromic properties. Its unique mechanoresponsive mechanism is based on the simultaneous configurational variation of its phenazine and phenyl moieties, facilitated by a worm-gear structure. We affirm mDPAC's complex mechanochemical response and elucidate its mechanotransduction mechanism through our experimental emission data and comprehensive DFT and MD simulations. The compatibility of mDPAC with hydrogels is particularly notable, highlighting its potential for applications in aqueous biological environments as a dynamic molecular force sensor and mapping tool. Moreover, mDPAC's multicolored mechanochromic responses enable direct force sensing, visual detection, and real-time quantification, paving the way for integrating molecular gears into bulk materials for precise and real-time mechanical force sensing.