title: Controlling Hydrogel Mechanics via Bio-Inspired Polymer-Nanoparticle Bond Dynamics.
abstract: Interactions between polymer molecules and inorganic nanoparticles can play a dominant role in nanocomposite material mechanics, yet control of such interfacial interaction dynamics remains a significant challenge particularly in water. This study presents insights on how to engineer hydrogel material mechanics via nanoparticle interface-controlled cross-link dynamics. Inspired by the adhesive chemistry in mussel threads, we have incorporated iron oxide nanoparticles (Fe3O4 NPs) into a catechol-modified polymer network to obtain hydrogels cross-linked via reversible metal-coordination bonds at Fe3O4 NP surfaces. Unique material mechanics result from the supra-molecular cross-link structure dynamics in the gels; in contrast to the previously reported fluid-like dynamics of transient catechol-Fe(3+) cross-links, the catechol-Fe3O4 NP structures provide solid-like yet reversible hydrogel mechanics. The structurally controlled hierarchical mechanics presented here suggest how to develop hydrogels with remote-controlled self-healing dynamics.
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
authors.forename: Qiaochu
authors.initials: Q
authors.lastname: Li
authors.affiliation: Chemistry of Life Processes Institute, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Devin G
authors.initials: DG
authors.lastname: Barrett
authors.affiliation: Department of Bioengineering and Materials Science and Engineering, University of California, Berkeley , 210 Hearst Mining Building, Berkeley, California 94720-1760, United States.
authors.forename: Phillip B
authors.initials: PB
authors.lastname: Messersmith
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
authors.forename: Niels
authors.initials: N
authors.lastname: Holten-Andersen
mesh_terms: D000818:Animals; D040761:Biomimetic Materials / Q000737:chemistry; D049872:Bivalvia / Q000737:chemistry; D002396:Catechols / Q000737:chemistry*; D004548:Elasticity; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D015394:Molecular Structure; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D018583:Pliability; D012212:Rheology
chemical_list: D002396:Catechols; D020100:Hydrogels; D007501:Iron; D052203:Ferrosoferric Oxide
keywords: bio-inspired metal-coordinate polymers; nanocomposite hydrogels; organic−inorganic interface; polymer physics; rheology; supra-molecular assembly