The design of polymeric materials that change color under applied mechanical force is a developing area of interest for stress sensing applications. In polymer mechanochemistry, mechanical force is transmitted via polymer chains to stress sensitive molecules called mechanophores to activate a chemical reaction. Naphthopyran is a mechanophore that undergoes a ring-opening reaction under force in polymeric materials to generate a highly colored merocyanine dye. In this presentation, we introduce a series of naphthopyran mechanophores that generate merocyanine dyes with highly tunable visible absorption properties and thermal reversion kinetics. Diversification of a common naphthopyran scaffold using straightforward synthetic strategies affords a library of mechanophores that are incorporated into crosslinked polydimethylsiloxane (PDMS) networks, affording materials that produce color in tension that varies from orange-yellow to purple with rates of color-fading controlled over three orders of magnitude. The modularity of this platform enables access to polymers that exhibit complex force-reporting and multimodal stimuli-responsive behavior such as multicolor mechanochromism and visually orthogonal responses to light and force.

Controlling color and fading properties of mechanochromic polydimethylsiloxane materials

ACS Spring Meeting 2021

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