Triggering chemical reactions by mechanical stimuli has become important as it enables the direct transformation of destructive effects, like structural damage or leaking material properties, to productive applications, usable for instance in the field of self-healing and stress-sensing materials. For this purpose, a series of poly(styrene) and polyurethane based mechanophores were designed containing copper(I)-bis(<i>N</i>-heterocyclic carbene) (NHC) moieties, inactive in their initial state, but turned to an active state upon cleavage of one shielding NHC ligand solely by force. These catalysts are able to trigger a fluorogenic copper(I) azide alkyne cycloaddition (CuAAC) of initially non-fluorescent substrates, which are embedded into the matrix material forming a highly fluorescent reporter dye. The quantification of fluorescence via fluorescence spectroscopy reveals different activation efficiencies by varying the architecture of the mechanophore. The chain length dependence (linear), the presence of multiple copper(I) centers and the three-dimensional force transmission within a network architecture were investigated, emphasizing the network-based approach as the most promising candidate. The effects of different stress rates applied forces and crosslinking densities were investigated in respect to the mechanophore activation. Thus, the potential for stress-sensing materials, easily tunable by variation of the basic components could be proven highlighting their versatility and make them beneficial for a broad range of technical applications.

Mechanochemical activation of copper(I) bis(NHC) complexes in polymer matrices and their potential as stress sensing material

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.