{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T16:00:46Z","timestamp":1790179246398,"version":"4.1.0"},"reference-count":45,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T00:00:00Z","timestamp":1790121600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T00:00:00Z","timestamp":1790121600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Small"],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>Transmission electron microscopy (TEM) is routinely used to validate the morphological uniformity of colloidal nanoparticles. These assessments fail to provide direct evidence of steric isolation of nanoparticles, often resulting in unforeseen failures during downstream engineering processes. This study quantitatively deciphers interfacial ligand kinetics under synthesis conditions to establish a rigorous thermodynamic boundary for the colloidal stability of upconversion nanoparticles (UCNPs). Despite negligible changes in TEM, extended thermal stress triggers a catastrophic loss of dispersibility, verified by DLS analysis. Comprehensive analysis via FTIR, XPS, and TGA indicates that the instability arises from the continuous desorption of oleic acid, triggered by alterations in the ligand\u2010binding modes under thermal stress. By modeling ligand\u2010chelation dynamics via the Arrhenius equation, we suggest a critical grafting density of  to ensure the long\u2010term colloidal stability over 1 year. This demonstrates that monitoring grafting density relative to a critical threshold enables direct prediction of nanoparticle aggregation, a feat unattainable by synthesis parameters commonly documented in the literature. Neglecting this parameter causes downstream defects like multi\u2010core encapsulation and poor thin\u2010film quality. This work offers a quantitative engineering guideline for robust nanomaterial fabrication by replacing routine morphological assessment with precise interfacial control.<\/jats:p>","DOI":"10.1002\/smll.75854","type":"journal-article","created":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T15:07:35Z","timestamp":1790176055000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Quantitative Analysis of Ligand\u2010Chelation Dynamics and Critical Grafting Density for the Long\u2010Term Steric Isolation of Colloidal Upconversion Nanoparticles"],"prefix":"10.1002","author":[{"given":"Won\u2010Woo","family":"Noh","sequence":"first","affiliation":[{"name":"School of Chemical Engineering Sungkyunkwan University (SKKU)  Suwon Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0237-6664","authenticated-orcid":false,"given":"Byeong\u2010Seok","family":"Moon","sequence":"additional","affiliation":[{"name":"School of Chemical Engineering Sungkyunkwan University (SKKU)  Suwon Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Geon\u2010Dae","family":"Kim","sequence":"additional","affiliation":[{"name":"School of Chemical Engineering Sungkyunkwan University (SKKU)  Suwon Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4362-0990","authenticated-orcid":false,"given":"Young Mee","family":"Jung","sequence":"additional","affiliation":[{"name":"Department of Chemistry Kangwon National University  Chunchon Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9084-3516","authenticated-orcid":false,"given":"Bo\u2010In","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Semiconductor Science and Technology Jeonbuk National University  Jeonju Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2753-0955","authenticated-orcid":false,"given":"Dong\u2010Hwan","family":"Kim","sequence":"additional","affiliation":[{"name":"School of Chemical Engineering Sungkyunkwan University (SKKU)  Suwon Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,23]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"crossref","first-page":"5161","DOI":"10.1021\/cr400425h","article-title":"Upconversion Nanoparticles: Design, Nanochemistry, and Applications in Theranostics","volume":"114","author":"Chen G.","year":"2014","journal-title":"Chemical Reviews"},{"key":"e_1_2_9_3_1","doi-asserted-by":"crossref","first-page":"924","DOI":"10.1038\/nnano.2015.251","article-title":"Controlling Upconversion Nanocrystals for Emerging Applications","volume":"10","author":"Zhou B.","year":"2015","journal-title":"Nature Nanotechnology"},{"key":"e_1_2_9_4_1","doi-asserted-by":"crossref","first-page":"335","DOI":"10.3390\/bios15060335","article-title":"Recent Progress on Rare\u2010Earth\u2010Doped Upconversion Nanomaterials for Bioassay Applications","volume":"15","author":"Xu J.","year":"2025","journal-title":"Biosensors"},{"key":"e_1_2_9_5_1","doi-asserted-by":"crossref","first-page":"2499","DOI":"10.1021\/acsami.2c12370","article-title":"Lanthanide\u2010Doped Upconversion Nanoparticles: Exploring a Treasure Trove of Nir\u2010Mediated Emerging Applications","volume":"15","author":"Malhotra K.","year":"2023","journal-title":"ACS Applied Materials Interfaces"},{"key":"e_1_2_9_6_1","doi-asserted-by":"crossref","first-page":"6907","DOI":"10.1039\/D5MA00542F","article-title":"Lanthanide\u2010Based Ucnps: Toxicity Evaluation and Interaction of Ultrasmall Core Vs. 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