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Polychaete worms display a remarkable jaw structure, where a gradient in metal-ligand coordination down thelength of the jaw results in a shift from hard to soft mechanics. To mimic these gradient structures, a Zn-coordinated supramolecular polymer is crosslinked into a covalent matrix to afford supramolecular semi-in-terpenetrating networks (SIPNs). These SIPN materials exhibit improved mechanics with a lower supramolecularcontent (30 wt%), allowing for energy dissipation through cavitation to increase material toughness. The shift inmechanical behavior is further attributed to the morphology, where the size of the phase-separated droplets andnature of the continuous phase in these SIPNs contributes to the material mechanics. Furthermore, chemicalgradients are applied to these systems through exposure to a competitive ligand, offering control over the lo-calization of supramolecular interactions. These materials offer a framework to mediate mechanics whilemaintaining the ability to program gradient supramolecular interactions.
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Nested non-covalent interactions expand the functions of supramolecular polymer networks
Abstract Supramolecular polymer networks contain non-covalent cross-links that enable access to broadly tunable mechanical properties and stimuli-responsive behaviors; the incorporation of multiple unique non-covalent cross-links within such materials further expands their mechanical responses and functionality. To date, however, the design of such materials has been accomplished through discrete combinations of distinct interaction types in series, limiting materials design logic. Here we introduce the concept of leveraging “nested” supramolecular crosslinks, wherein two distinct types of non-covalent interactions exist in parallel, to control bulk material functions. To demonstrate this concept, we use polymer-linked Pd2L4metal–organic cage (polyMOC) gels that form hollow metal–organic cage junctions through metal–ligand coordination and can exhibit well-defined host-guest binding within their cavity. In these “nested” supramolecular network junctions, the thermodynamics of host-guest interactions within the junctions affect the metal–ligand interactions that form those junctions, ultimately translating to substantial guest-dependent changes in bulk material properties that could not be achieved in traditional supramolecular networks with multiple interactions in series.
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- Award ID(s):
- 2116298
- PAR ID:
- 10506309
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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