Force-Responsive Polymers, Networks and Catalysts

The acceleration of chemical reactions under mechanical stress has been known since the earliest days of polymer science. Once limited to simple bond dissociation reactions in polymer chains, mechanical force can now be used to produce a wide array of productive chemistry. The development of so-called "covalent mechanochemistry", has allowed chemists to challenge and support classically held models of chemical reactivity, impacting both synthetic chemistry and material science. This dissertation describes efforts to develop molecular tools that respond to stress with focus on the following: (I) developing new mechanochemically reactive organic molecules (mechanophores) that exhibit molecular level stress-relief and stress-strengthening in linear polymers under stress; (II) incorporating weak and transient coordination cross-links into covalent gels, greatly enhancing their strength and toughness in response to macroscopic stress; (III) constructing catalytic systems with tunable selectivity for the amplification of mechanochemical signals. While a wide-range of fields may be impacted, the unifying theme in this work is the development of materials with rich and robust molecular responses to traditionally destructive forces.