Microscale manipulation of bond exchange reactions in photocurable vitrimers with a covalently attachable photoacid generator

Research output: Contribution to journalArticleResearchpeer-review

Authors

  • Roman Korotkov
  • Walter Alabiso
  • Max Schmallegger
  • Yang Li
  • Elisabeth Rossegger

External Organisational units

  • Polymer Competence Center Leoben GmbH
  • Technische Universität Graz

Abstract

Vitrimers are polymer networks with covalent bonds that undergo reversible exchange reactions and rearrange their topology in response to an external stimulus. The temperature-dependent change in viscoelastic properties is conveniently adjusted by selected catalysts. In these thermo-activated systems, the lack in spatial control can be overcome by using photolatent catalysts. Herein, we advance this concept to locally manipulate bond exchange reactions on a single digit microscale level. For this, we synthetize a linkable non-ionic photoacid generator, which is covalently attached to a thiol-click photopolymer. UV induced deprotection of the photoacid yields a strong immobilized sulfonic acid species, which is able to efficiently catalyze transesterification reactions. Covalent attachment of the formed acid prevents migration/leaching processes and enables a precise tuning of material properties. As proof of concept, positive toned microstructures with a resolution of 5 μm are inscribed in thin films using direct two-photon absorption laser writing and subsequent depolymerization. In addition, the possibility to locally reprogram bulk material properties is demonstrated by performing a post-modification reaction with ethylene glycol and carboxylic acids. The Young's modulus is varied between 3.3 MPa and 11.9 MPa giving rise to the versatility of the newly introduced catalysts for creating light processable and transformable materials.

Details

Original languageEnglish
Pages (from-to)16271-16280
Number of pages10
JournalChemical science
Volume15.2024
Issue number39
DOIs
Publication statusPublished - 3 Sept 2024