{
  "abstract": "Covalent adaptable networks (CANs) based on boronic acid–ester exchange undergo rapid network reconfiguration in ambient conditions, making them useful materials for biomedical applications. The combination of photoswitches and dynamic bonds imparts reversible spatiotemporal control over mechanical properties for smart and responsive materials. Here, we report azopyrazole boronic acids that undergo rapid photoisomerization to their metastable Z isomers, which have extremely long thermal half-lives (over a year at 25 °C) and a 3-fold enhancement in binding affinity for diols compared to the E isomer. When incorporated into hydrogels, these photoswitchable dynamic bonds enable reversible changes in stiffness and stress relaxation time with at least 6 cycles of visible and UV light. Despite only containing dynamic crosslinks, these hydrogels are comparable in stiffness to our previously reported hybrid materials containing dynamic azobenzene boronic ester and static bis(acrylamide) crosslinks. This work demonstrates an alternative strategy to tuning boronic acid-ester equilibria with light while maintaining strong binding in both isomers.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL, United States of America, 60208"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Mara L. Paterson"
    },
    {
      "affs": [
        0
      ],
      "name": "Tomas Castillo"
    },
    {
      "affs": [
        0
      ],
      "name": "Sarah Lin"
    },
    {
      "affs": [
        0
      ],
      "name": "Julia A. Kalow",
      "orcid": "0000-0002-4449-9566"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f7jczv1er7yvf.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15008994/v1",
  "fulltext_url": null,
  "id": "f7jczv1er7yvf",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008994/v1",
  "language": null,
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1313|Hydrogels: synthesis, properties, applications"
    ]
  ],
  "openalex": "W7213454676",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008994/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-17",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/f7jczv1er7yvf.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:19Z",
      "native_id": "10.26434/chemrxiv.15008994",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008994/v2"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:1313|Hydrogels: synthesis, properties, applications",
      "subfield": "general"
    }
  ],
  "title": "Azopyrazole boronic ester crosslinks with long thermal half-lives for phototunable viscoelastic hydrogels",
  "title_text": "Azopyrazole boronic ester crosslinks with long thermal half-lives for phototunable viscoelastic hydrogels",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:21Z",
  "url": "https://research.draconitic.com/paper/f7jczv1er7yvf",
  "venue": "ChemRxiv",
  "versions": []
}