Linear Viscoelasticity and Cation Conduction in Polyurethane Sulfonate Ionomers with Ions in the Soft Segment–Multiphase Systems

Highly Ordered Gyroid Nanostructured Polymers: Facile Fabrication by Polymerizable Pluronic Surfactants

Highly ordered, network-nanostructured polymers offer compelling geometric features and application potential. However, their practical utilization is hampered by the restricted accessibility. Here, we address this challenge using commercial Pluronic surfactants with a straightforward modification of tethering polymerizable groups. By leveraging lyotropic self-assembly, we achieve facile production of double-gyroid mesophases, which are subsequently solidified via photoinduced cross-linking. The exceptionally ordered periodicities of Ia3d symmetry in the photocured polymers are unambiguously confirmed by synchrotron small-angle X-ray scattering (SAXS), which can capture single-crystal-like diffraction patterns. Electron density maps reconstructed from SAXS data complemented by transmission electron microscopy analysis further elucidate the real-space gyroid assemblies. Intriguingly, by tuning the cross-linking through thiol-acrylate chemistry, the mechanical properties of the polymer are modulated without compromising the integrity of Ia3d assemblies. The 3-D percolating gyroid nanochannels demonstrate an ionic conductivity that surpasses that of disordered structures, offering promising prospects for scalable fabrication.

Hydrogen Bonds-Pinned Entanglement Blunting the Interfacial Crack of Hydrogel-Elastomer Hybrids

Anchoring a layer of amorphous hydrogel on an antagonistic elastomer holds potential applications in surface aqueous lubrication. However, the interfacial crack propagation usually occurs under continuous loads for amorphous hydrogel, leading to the failure of hydrogel interface. This work presents a universal strategy to passivate the interfacial cracks by designing a hydrogen bonds-pinned entanglement (Hb-En) structure of amorphous hydrogel on engineering elastomers. The unique Hb-En structure is created by pinning well-tailored entanglements via covalent-like hydrogen bonds, which can amplify the delocalization of interfacial stress concentration and elevate the necessary fracture energy barrier within hydrogel interface. Therefore, the interfacial crack propagation can be suppressed under single and cyclic loads, resulting in a high interfacial toughness over 1650 J m-2 and an excellent interfacial fatigue threshold of 423 J m-2. Such a strategy universally works on blunting the interfacial crack between hydrogel coating and various elastomer materials with arbitrary shapes. The superb fatigue-crack insensitivity at the interface allows for durable aqueous lubrication of hydrogel coating with low friction.

Fast Li+ Transport Polyurethane-Based Single-Ion Conducting Polymer Electrolyte with Sulfonamide Side chains in the Hard Segment for Lithium Metal Batteries

Single-ion conducting polymer electrolytes (SICPEs) are considered as one of the most promising candidates for achieving lithium metal batteries (LMBs). However, the application of traditional SICPEs is hindered by their low ionic conductivity and poor mechanical stability. Herein, a self-standing and flexible polyurethane-based single-ion conductor membrane was prepared via covalent tethering of the trifluoromethanesulfonamide anion to polyurethane, which was synthesized using a facile reaction of diisocyanates with poly(ethylene oxide) and 3,5-diaminobenzoic acid (or 3,5-dihydroxybenzoic acid). The polymer electrolyte exhibited excellent ionic conductivity, mechanical properties, lithium-ion transference number, thermal stability, and a broad electrochemical window because of the bulky anions and unique two-phase structures with lithium-ion nanochannels in the hard domains. Consequently, the plasticized electrolyte membrane showed exceptional stability and reliability in a Li||Li symmetric battery. The assembled LiFePO4||Li battery exhibited an outstanding capacity (∼180 mA h g-1), Coulombic efficiency (>96%), and capacity retention. This research provides a promising polymer electrolyte for high-performance LMBs.

Ionic Liquid-Grafted Polyamide 6 by Radiation-Induced Grafting: New Strategy To Prepare Covalently Bonded Ion-Containing Polymers and their Application as Functional Fibers

Ion-containing polymers are of great importance for its unique structure and properties. An ion-containing polyamide 6 (PA6) was prepared by grafting an ionic liquid, 1-vinyl-3-butyl imidazole chloride [VBIM][Cl], onto the main chain of PA6 using radiation-induced grafting. The grafted ions on the PA6 main chain significantly influenced the structure and properties of the PA6 matrix. The ions form nanoscale aggregations without inducing further microphase separation. Acting as a physical "cross-linking point," each aggregation enhanced inter/intrachain interactions, which increased the viscosity, storage modulus, and relaxation time and reduced the ability of PA6 to crystallize. However, the bulky cations of the grafted ionic liquid can also be seen as "spacers," which enlarge the distance among chains and reduce the strength of the hydrogen bonds inherently existing in the PA6 matrix. The "cross-linking points" and "spacers" of ions as well as the hydrogen bonds of PA6 take effect collectively in the system. Moreover, the ion-containing PA6 retains good melt processability compared with PA6, despite increased viscosity, and can be easily melt-spun into fibers. Fibers prepared from ion-containing PA6 showed improved mechanical properties and antistatic performance and exhibited the expected antibacterial properties, especially with regard to Escherichia coli. Inspiringly, covalently bonding ions to the PA6 main chain offers a new strategy for fabricating functional fibers with permanent antistatic and antibacterial properties.