Revealing filler-matrix structure of hydrogel-inorganic nanocomposite across multiple length scales by direct observation

Revealing filler-matrix structure of hydrogel-inorganic nanocomposite across multiple length scales by direct observation | 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 Article Revealing filler-matrix structure of hydrogel-inorganic nanocomposite across multiple length scales by direct observation Takayuki Nonoyama, Maradhana Agung Marsudi, Masahiro Yoshida, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9368592/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Hydrogel–inorganic nanocomposites are widely used to enhance the mechanical performance of hydrogels, yet a direct understanding of how filler–matrix interfaces govern their internal structure across multiple length scales and influence macroscopic properties remains elusive. This limitation arises from the lack of techniques capable of resolving local structures in highly hydrated polymer networks without inducing structural perturbation. Here, we directly visualize the internal architecture of hydrogel nanocomposites using a transmission electron microscopy (TEM) approach that combines selective mineral staining with a supporting network to preserve the native structure. This enables real-space observation of filler–matrix organization across nano-, micro-, and mesoscale, including interfacial structure, matrix perturbation near fillers, and filler dispersion and network formation. We reveal how interfacial chemistry dictates structural organization and its evolution under swelling and mechanical loading. Proper surface treatment of fillers promotes strong interfacial bonding, suppresses void formation, and induces the formation of load-bearing polymer chains bridging neighboring fillers, leading to a percolated network structure. These structural features govern distinct failure mechanisms and quantitatively correlate with enhanced stiffness, improved crack resistance, and suppressed swelling. Our findings provide direct experimental evidence of multiscale structure–property relationships that have previously been inferred only indirectly, establishing a framework for understanding and designing hydrogel nanocomposites. Physical sciences/Materials science/Soft materials/Gels and hydrogels Physical sciences/Materials science/Techniques and instrumentation/Microscopy/Transmission electron microscopy Physical sciences/Materials science/Soft materials/Rheology Physical sciences/Materials science/Techniques and instrumentation/Imaging techniques Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryInformation.docx Supplementary Information SupplementaryMovieS1.mp4 Pure shear test Cite Share Download PDF Status: Under Review 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9368592","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":630283489,"identity":"ceb9a7b8-fd87-43ca-88fb-0283b153ddd5","order_by":0,"name":"Takayuki 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