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{"title":"InjectablenPoly(<i>N</i>‑isopropylacrylamide)/Poly(vinylpyrrolidone)nInterpenetrating Network Hydrogels Formed via Hydrazone/DisulfidenCross-Linking","authors":"Trevor Gilbert (1506739), Matthew A. Campea (13235991), Nahieli Preciado Rivera (14076450), Michael Majcher (16872624), Richard Alsop (4445350), Mouhanad Babi (4617367), Thomas Kalab (16872627), Jose Moran-Mirabal (3205122), Maikel Rheinstadter (16872630), Todd Hoare (1418734)","doi":"10.1021/acs.macromol.3c00045.s001","DOIUrl":"https://doi.org/10.1021/acs.macromol.3c00045.s001","url":null,"abstract":"Injectable <i>in situ</i> gelling interpenetratingnnetworknhydrogels in which both interpenetrating phases can independentlyngel upon injection offer significant potential in applications ifntheir internal structure can be rationally controlled. Herein, wenreport the fabrication and nanostructural characterization of poly­(<i>N</i>-isopropylacrylamide) (PNIPAM)/poly­(vinylpyrrolidone) (PVP)ninjectable interpenetrating polymer networks constructed based onna combination of hydrazone (PNIPAM) and disulfide (PVP) cross-linking.nCompared to previously reported hydrazone/thiosuccinimide IPN formation,ndisulfide cross-linking is significantly slower than hydrazone cross-linking,nenabling the generation of tunable internal phase morphologies innthe injectable IPNs as a function of PVP molecular weight and degreenof thiolation. Results from bulk rheology, polarity-sensitive fluorescencenmeasurements, STORM super-resolution fluorescence microscopy, andncontrast-matched small-angle neutron scattering measurements suggestnthat domain formation on the SANS-accessible length scale is drivennby the rapid PNIPAM gelation that largely excludes PNIPAM from thenPVP-rich domains but results in significant PVP entrapment withinnthe PNIPAM-rich domain. Furthermore, PVP precursor polymers with lowernmolecular weights (i.e., reduced viscosities) and/or lower degreesnof thiolation result in IPNs that undergo significant structural reconfigurationnupon heating above the volume phase transition of the PNIPAM phase,na result correlated to the capacity of the thermodynamically favorablenPNIPAM phase transition to reconfigure the weaker and dynamic PVP-disulfidenphase to maximize the degree of PNIPAM phase collapse. Overall, regulatingnthe relative gelation kinetics of the two interpenetrating <i>in situ</i> gelling phases results in tunable morphologies ofnrelevance to the potential applications of such materials.","PeriodicalId":523778,"journal":{"name":"Figshare","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1753-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147921780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}