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The Activation Efficiency of Mechanophores Can Be Modulated by Adjacent Polymer Composition

preprint
submitted on 06.11.2020, 10:19 and posted on 06.11.2020, 10:54 by Sourabh Kumar, Tim Stauch

The activation efficiency of mechanophores in stress-responsive polymers is generally limited by the competing process of unspecific scission in other parts of the polymer chain. Here it is shown that the linker between the mechanophore and the polymer backbone determines the force needed to activate the mechanophore. Using quantum chemical methods, it is demonstrated that the activation forces of three mechanophores (Dewar benzene, benzocyclobutene and gem-dichlorocyclopropane) can be adjusted over a range of almost 300% by modifying the chemical composition of the linker. The results are discussed in terms of changes in electron density, strain distribution and structural parameters during the rupture process. Using these findings it is straightforward to either significantly enhance or reduce the activation rate of mechanophores in stress-responsive materials, depending on the desired use case. The methodology is applied to switch a one-step “gating” of a mechanochemical transformation to a two-step process.

History

Email Address of Submitting Author

tstauch@uni-bremen.de

Institution

University of Bremen

Country

Germany

ORCID For Submitting Author

0000-0001-7599-3578

Declaration of Conflict of Interest

The authors declare no conflict of interest

Version Notes

Initial submission; not yet peer-reviewed

Exports