Spatial and Temporal Control of Photomediated Disulfide-Ene and Thiol-Ene Chemistries for Two-Stage Polymerizations

A new strategy is reported for the design and synthesis of high sulfur-containing materials for potential use in covalent adaptable networks and optical materials by combining photomediated thiol-ene- and disulfide-ene-based polymerization reactions. Taking advantage of the relative reaction rates to differentiate sequentially between the thiol-ene and disulfide-ene conjugations, these reactions were performed semiorthogonally to produce polymer networks of controlled architecture. Kinetic analysis demonstrates that the thiol-ene reaction is approximately 30 times faster than the disulfide-ene reaction, enabling spatial and temporal manipulation of material properties via dual-cure networks and photopatterning. A two-stage polymerization approach was implemented with increases in modulus in the second stage of 2-3 orders of magnitude accompanied by increases in the glasstransition temperature of more than 15 degrees C. Additionally, the thiol-ene reaction in the presence of a disulfide yields materials capable of simultaneous network development and stress relaxation through dynamic bond exchange during in situ polymerization.

Automated summary

A new strategy combining photomediated thiol-ene and disulfide-ene-based polymerization reactions is reported for the design and synthesis of high sulfur-containing materials for potential use in covalent adaptable networks and optical materials. By taking advantage of the relative reaction rates and semiorthogonally performing these reactions, controlled architecture polymer networks were produced. The study demonstrates the differential reaction rates between thiol-ene and disulfide-ene reactions, enabling spatial and temporal manipulation of material properties through dual-cure networks and photopatterning.