Strategic covalent bond transformations using mechanical force

Abstract

The use of mech. force to selectively activate covalent bond transformations is emerging as a powerful method to access stimuli-responsive polymers for applications ranging from sensing to drug delivery. In polymer mechanochem., polymer chains transduce mech. stress to force-sensitive mols. called mechanophores that can be designed to undergo a wide variety of chem. reactions. Mechanochem. reactivity arises from a distortion of the potential energy surface under large forces, which fundamentally changes the reaction landscape. Force-induced chem. reactions that produce a change in optical properties such as color or luminescence are particularly useful because they enable mol. level stress sensing by simple visual detection methods. Mech. triggered release of small mols. is also an underdeveloped, but potentially powerful approach for sensing and delivery. Our recent developments on a mechanophore design strategy that decouples mech. activation from a functional response will be presented. This mech. gated reaction methodol. establishes unique opportunities for understanding and exploiting the structural features that govern mechanochem. reactions and creating stimuli-responsive polymers that impact a variety of useful technologies.