Paper Number
GN38                         My Program 

Session
Self-assemblies, Gels and Networks

Title
Enhancing the re-processability of photo-recyclable polymer networks using molecular design and in situ photo-rheology

Presentation Date and Time
October 22, 2025 (Wednesday) 11:10

Track / Room
Track 2 / Sweeney Ballroom B

Authors (Click on name to view author profile)

  1. Quirk, Eleanor L. (Stanford University, Chemical Engineering)
  2. Pereira dos Santos, Camily (Stanford University, Chemical Engineering)
  3. Burroughs, Michael C. (Stanford University, Chemical Engineering)
  4. Wirtz, Brendan M. (Stanford University, Chemical Engineering)
  5. Schloemer, Tracy H. (Stanford University, Electrical Engineering)
  6. Congreve, Daniel N. (Stanford University, Electrical Engineering)
  7. Mai, Danielle J. (Stanford University, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Eleanor L. Quirk1, Camily Pereira dos Santos1, Michael C. Burroughs1, Brendan M. Wirtz1, Tracy H. Schloemer2, Daniel N. Congreve2 and Danielle J. Mai1
1Chemical Engineering, Stanford University, Stanford, CA 94305; 2Electrical Engineering, Stanford University, Stanford, CA 94305

Speaker / Presenter 
Quirk, Eleanor L.

Keywords
experimental methods; gels; networks; polymer solutions; sustainability

Text of Abstract
Polymer networks are versatile materials used in consumer products, biomedical materials, and 3D printing. The ubiquity of manufactured polymer networks leads to plastic waste generation and environmental harm, as these networks are built to last and rarely designed for sustainable end-of-life reprocessing. To investigate polymer network recycling, we report the time-resolved material evolution of model photo-responsive polymers during network formation, deconstruction, and re-formation using in situ photo-rheology. The model system comprises multi-arm star polyethylene glycol end-functionalized with the photo-crosslinking molecule anthracene (PEG-anthracene). PEG-anthracene undergoes network formation upon irradiation with ultraviolet light (UVA, 365 nm) and network deconstruction upon irradiation with short-wavelength ultraviolet light (UVC, 265 nm). PEG-anthracene recyclability is increased by reducing anthracene crosslink density and maximizing un-crosslinking. Thus, by reducing the number of arms per polymer star, the concentration of polymer in solution, and the duration of UVA light exposure to the minimum values required for network formation, PEG-anthracene recyclability is enhanced. These findings demonstrate an opportunity for spatiotemporal-control of reprocessible photo-responsive polymer networks.