{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T03:41:11Z","timestamp":1788406871854,"version":"build-2803163510"},"reference-count":34,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2023,7,21]],"date-time":"2023-07-21T00:00:00Z","timestamp":1689897600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>The common, commercial reversible thermochromic (RT) melamine\u2013formaldehyde resin microcapsules containing formaldehyde are very harmful to human health. To address this issue, we successfully prepared a novel formaldehyde-free microcapsule via interfacial polymerization using RT compositions as the core and poly(urethane-urea) (PUU) as the shell. The core material consisted of a color former (crystal violet lactone), a developer (bisphenol AF), and a solvent (methyl stearate). To optimize the synthesis of the microcapsules, an L9 (34) orthogonal design and single-factor experiments were employed to analyze the effects of four factors (N3300-to-L75 shell material mass ratio, core-to-shell material mass ratio, emulsifier concentration, and shear rate during emulsification) on the encapsulation efficiency. The results showed that the optimal parameter values were as follows: a shear rate of 2500 rpm, N3300-to-L75 shell material mass ratio of 1:4, core-to-shell material mass ratio of 11:5, and emulsifier concentration of 3.5%. The influence of the shear rate on the particle size and distribution, surface morphology, dispersibility, and reversible thermochromic properties of the microcapsules was investigated. Furthermore, analyses on the phase-change characteristics, thermal stability, ultraviolet aging, and solvent and acid\u2013base resistances of the microcapsules were conducted systematically. Finally, a reversible thermochromic mark containing the RTPUU microcapsules was designed and fabricated, which could be used against falsification. Moreover, these RTPUU microcapsules can be potentially used for anticounterfeiting applications.<\/jats:p>","DOI":"10.3390\/ma16145150","type":"journal-article","created":{"date-parts":[[2023,7,24]],"date-time":"2023-07-24T01:15:45Z","timestamp":1690161345000},"page":"5150","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":38,"title":["Reversible Thermochromic Microcapsules and Their Applications in Anticounterfeiting"],"prefix":"10.3390","volume":"16","author":[{"given":"Haisheng","family":"Liu","sequence":"first","affiliation":[{"name":"School of Physics and Electronics, Hunan University, Changsha 410082, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuhao","family":"Deng","sequence":"additional","affiliation":[{"name":"Materials Interfaces Center, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yang","family":"Ye","sequence":"additional","affiliation":[{"name":"Materials Interfaces Center, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xingqiang","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Physics and Electronics, Hunan University, Changsha 410082, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1016\/j.solener.2016.10.011","article-title":"Fabrication and characterization of microcapsulated phase change materials with an additional function of thermochromic performance","volume":"139","author":"Wang","year":"2016","journal-title":"Sol. 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