The design of mechanochromic materials has garnered significant interest in the emerging field of polymer mechanochemistry for force sensing and other applications. In this field, force-sensitive molecules called mechanophores are covalently embedded in polymer chains to create materials that are responsive to mechanical stimuli. While many color-changing mechanophores have been studied, few retain their colored state for long periods of time after stress relaxation, and furthermore, the generation of multiple colors from a single mechanophore has not been reported. Both of these features are desirable for creating materials for multicolor mechanical soft lithography. Here, we describe a new mechanophore platform that undergoes a mechanically gated chromogenic reaction in the presence of an extrinsic small molecule developing reagent. The color of the generated product can be selected by the choice of the small molecule developer. The unique modularity of this gated system allows for multicolor mechanical lithography by sequential application of mechanical force and small molecule developer to a polydimethylsiloxane (PDMS) elastomer incorporating the mechanophore as a crosslinker.

Multicolor mechanical lithography in polymeric materials

ACS Spring 2022

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