Linking Long-range Surface-Induced Mobility Enhancement and Intrinsic Fragility of Polymer Glasses

Linking Long-range Surface-Induced Mobility Enhancement and Intrinsic Fragility of Polymer Glasses | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Linking Long-range Surface-Induced Mobility Enhancement and Intrinsic Fragility of Polymer Glasses Haoran Nie, Xiwen Chen, Xiyue Li, Zongyi Ma, Rui Zhang, Ophelia Tsui This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8857592/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Surface-induced mobility enhancement propagates into polymer glasses over distances from nanometers to micrometers. The discovery of a mobile surface “bilayer” structure—comprising a nanoscale outer layer and a microscale sublayer—provides insight into this significant variability in propagation length. However, the origin of the extensive microscale sublayer ( \(\:{h}_{\text{t}}\) ) remains elusive. Using dynamic mechanical analysis (DMA), we establish a strong correspondence between nanolayer mobility enhancement and \(\:{h}_{\text{t}}\) , both of which increase with the intrinsic fragility of polymer glass. Coarse-grained simulations confirm our experimental findings, revealing that enhanced molecular velocity at the surface initiates long-range shear-like excitation modes that penetrate deeper into the bulk as polymer fragility increases. This combination of experiment and simulation provides a unified framework that reconciles historical discrepancies regarding the free surface effect, establishing fragility as a critical parameter for predicting the relative sizes of surface-enhanced mobility and its propagation length across different polymers. Polymer Science Soft Condensed-matter Physics Physical Chemistry Materials Theory and Modeling Mobile surface layer Glass transition Polymer films Tg confinement effect Full Text Additional Declarations The authors declare no competing interests. Supplementary Files SINieChen.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8857592","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":590012660,"identity":"544793ff-71e3-4b47-8553-446c26bf41a0","order_by":0,"name":"Haoran Nie","email":"","orcid":"https://orcid.org/0009-0006-9234-1575","institution":"Hong Kong University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Haoran","middleName":"","lastName":"Nie","suffix":""},{"id":590014086,"identity":"35b16277-8679-4231-91bf-8c3280f3b594","order_by":1,"name":"Xiwen 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Glasses\u003c/strong\u003e\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[{"identity":"68157812-c0a4-4c9b-90b4-4c6f1522eeb1","identifier":"10.13039/501100002920","name":"Research Grants Council, University Grants Committee","awardNumber":"N_HKUST623/21 ","order_by":0},{"identity":"499e7df2-0f8e-4e5b-940e-d402e4c74e3e","identifier":"10.13039/501100002920","name":"Research Grants Council, University Grants Committee","awardNumber":"16300824","order_by":1}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"The Hong Kong University of Science and 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propagates into polymer glasses over distances from nanometers to micrometers. The discovery of a mobile surface \u0026ldquo;bilayer\u0026rdquo; structure\u0026mdash;comprising a nanoscale outer layer and a microscale sublayer\u0026mdash;provides insight into this significant variability in propagation length. However, the origin of the extensive microscale sublayer (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{h}_{\\text{t}}\\)\u003c/span\u003e\u003c/span\u003e) remains elusive. Using dynamic mechanical analysis (DMA), we establish a strong correspondence between nanolayer mobility enhancement and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{h}_{\\text{t}}\\)\u003c/span\u003e\u003c/span\u003e, both of which increase with the intrinsic fragility of polymer glass. Coarse-grained simulations confirm our experimental findings, revealing that enhanced molecular velocity at the surface initiates long-range shear-like excitation modes that penetrate deeper into the bulk as polymer fragility increases. This combination of experiment and simulation provides a unified framework that reconciles historical discrepancies regarding the free surface effect, establishing fragility as a critical parameter for predicting the relative sizes of surface-enhanced mobility and its propagation length across different polymers.\u003c/p\u003e","manuscriptTitle":"Linking Long-range Surface-Induced Mobility Enhancement and Intrinsic Fragility of Polymer Glasses","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-17 04:39:51","doi":"10.21203/rs.3.rs-8857592/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0159d866-5036-4b70-9244-58e2a5ef502e","owner":[],"postedDate":"April 17th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":62779986,"name":"Polymer Science"},{"id":62779987,"name":"Soft Condensed-matter Physics"},{"id":62779988,"name":"Physical Chemistry"},{"id":62779989,"name":"Materials Theory and Modeling"}],"tags":[],"updatedAt":"2026-04-17T04:39:51+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-17 04:39:51","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8857592","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8857592","identity":"rs-8857592","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}