This research would not be possible without generous support from NSF Award No. 2400010, ACS PRF 66560-DNI7, the Precourt Institute at @stanfordenergy.bsky.social, Arnold and Mabel Beckman Foundation, and NSF GRFP! 🙏

We envision this work will catalyze advances in polymer engineering and photochemical processing pathways to achieve closed-loop, reprocessable materials. ♻️

We supplemented photorheology with time-resolved UV-vis absorbance to draw connections between network mechanics and photochemical conversion. We identified molecular-scale mechanisms that underlie pathways to either network softening or deconstruction. 🛣️

For stiff networks of polymers with many arms, we observed network softening, but no return to a deconstructed polymer liquid. For soft networks of polymers with fewer arms, we observed deconstruction into liquids for a critical time before networks unexpectedly re-constructed.⏲️

We studied how polymer shape—number of arms per multi-arm star polymer—influenced network formation & deconstruction kinetics. Networks formed faster with increasing number of arms (agreeing with Flory–Stockmayer predictions), but networks didn't always deconstruct as expected. ⁉️

We employed a photochemical strategy in which UVA light promotes polymer network formation and UVC light enables network deconstruction. 💡

Mike Burroughs led this effort using in situ photorheology to quantify how we could use light to construct polymeric materials, deconstruct them back to liquid solutions, re-construct, and deconstruct again! 🛠️⚒️🛠️⚒️

We envision this resource being useful for budding roboticists and biomolecular engineers to consider unconventional stimuli-responsive mechanisms! Read it here: doi.org/10.1021/acs....

Woohoo! Congratulations, Kōnane!!