{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T15:57:44Z","timestamp":1773849464010,"version":"3.50.1"},"reference-count":19,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2019,4,30]],"date-time":"2019-04-30T00:00:00Z","timestamp":1556582400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>We report the development of an extrinsic, self-healing coating system that shows no fluorescence from intact coating, yellowish fluorescence in cracked regions, and greenish fluorescence in healed regions, thus allowing separate monitoring of cracking and healing of coatings. This fluorescence-monitoring self-healing system consisted of a top coating and an epoxy matrix resin containing mixed dye loaded in a single microcapsule. The dye-loaded microcapsules consisted of a poly(urea-formaldehyde) shell encapsulating a healing agent containing methacryloxypropyl-terminated polydimethylsiloxane (MAT-PDMS), styrene, a photo-initiator, and a mixture of two dyes: one that fluoresced only in the solid state (DCM) and a second that fluoresced dramatically in the solid than in the solution state (4-TPAE). A mixture of the healing agent, photo-initiator, and the two dyes was yellow due to fluorescence from DCM. On UV curing of this mixture, however, the color changed from yellow to green, and the fluorescence intensity increased due to fluorescence from 4-TPAE in the solid state. When a self-healing coating embedded with microcapsules containing the DCM\/4-TPAE dye mixture was scratched, the damaged region exhibited a yellowish color that changed to green after healing. Thus, the self-healing system reported here allows separate monitoring of cracking and healing based on changes in fluorescence color.<\/jats:p>","DOI":"10.3390\/molecules24091679","type":"journal-article","created":{"date-parts":[[2019,4,30]],"date-time":"2019-04-30T02:07:19Z","timestamp":1556590039000},"page":"1679","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Dual Monitoring of Cracking and Healing in Self-healing Coatings Using Microcapsules Loaded with Two Fluorescent Dyes"],"prefix":"10.3390","volume":"24","author":[{"given":"Young Kyu","family":"Song","sequence":"first","affiliation":[{"name":"Research Center for Green Fine Chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tae Hee","family":"Lee","sequence":"additional","affiliation":[{"name":"Research Center for Green Fine Chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Korea"},{"name":"Department of Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jin Chul","family":"Kim","sequence":"additional","affiliation":[{"name":"Research Center for Green Fine Chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kyu Cheol","family":"Lee","sequence":"additional","affiliation":[{"name":"Research Center for Green Fine Chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2207-3369","authenticated-orcid":false,"given":"Sang-Ho","family":"Lee","sequence":"additional","affiliation":[{"name":"Research Center for Green Fine Chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Seung Man","family":"Noh","sequence":"additional","affiliation":[{"name":"Research Center for Green Fine Chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0977-6265","authenticated-orcid":false,"given":"Young Il","family":"Park","sequence":"additional","affiliation":[{"name":"Research Center for Green Fine Chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,4,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1600657","DOI":"10.1002\/marc.201600657","article-title":"Fluorescence Detection of Microcapsule-Type Self-Healing, Based on Aggregation-Induced Emission","volume":"38","author":"Song","year":"2017","journal-title":"Macromol. 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