TY - JOUR
T1 - Dual monitoring of cracking and healing in self-healing coatings using microcapsules loaded with two fluorescent dyes
AU - Song, Young Kyu
AU - Lee, Tae Hee
AU - Kim, Jin Chul
AU - Lee, Kyu Cheol
AU - Lee, Sang Ho
AU - Noh, Seung Man
AU - Park, Young Il
N1 - Publisher Copyright:
© 2019 by the authors.
PY - 2019
Y1 - 2019
N2 - 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.
AB - 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.
KW - Aggregation-induced emission
KW - Dye-loaded microcapsule
KW - Extrinsic self-healing
KW - Self-healing detection
KW - Self-healing monitoring
UR - http://www.scopus.com/inward/record.url?scp=85065674571&partnerID=8YFLogxK
U2 - 10.3390/molecules24091679
DO - 10.3390/molecules24091679
M3 - Article
C2 - 31052146
AN - SCOPUS:85065674571
SN - 1420-3049
VL - 24
JO - Molecules
JF - Molecules
IS - 9
M1 - 1679
ER -