Strong and Tough Nanostructured Hydrogels and Organogels Prepared by Polymerization‐Induced Self‐Assembly

Abstract

In nature, the hierarchical structure of biological tissues endows them with outstanding mechanics and elaborated functions. However, it remains a great challenge to construct biomimetic hydrogels with well-defined nanostructures and good mechanical properties. Herein, polymerization-induced self-assembly (PISA) is for the first time exploited as a general strategy for nanostructured hydrogels and organogels with tailored nanodomains and outstanding mechanical properties. As a proof-of-concept, PISA of BAB triblock copolymer is used to fabricate hydrogels with precisely regulated spherical nanodomains. These nanostructured hydrogels are strong, tough, stretchable, and recoverable, with mechanical properties correlating to their nanostructure. The outstanding mechanical properties are ascribed to the unique network architecture, where the entanglements of the hydrophilic chains act as slip links that transmit the tension to the micellar crosslinkers, while the micellar crosslinkers dissipate the energy via reversible deformation and irreversible detachment of the constituting polymers. The general feasibility of the PISA strategy toward nanostructured gels is confirmed by the successful fabrication of nanostructured hydrogels, alcogels, poly(ethylene glycol) gels, and ionogels with various PISA formulations. This work has provided a general platform for the design and fabrication of biomimetic hydrogels and organogels with tailorable nanostructures and mechanics and will inspire the design of functional nanostructured gels.

Polymerization-induced self-assembly for the construction of nanostructured hydrogels

“…6a). 79 To verify this, we prepared a series of multiphase hydrogels by chain-extending the bifunctional poly(ethylene glycol) (PEG) macro-CTA (molecular weight: 20 kDa) with DAAm at a target solids content of 50 wt% (Fig. 6b).…”

“…With this strategy, a variety of tough multiphase gels, including organogels, PEG gels, and ionogels, were also produced, demonstrating its broad feasibility. 79…”

Tough Hydrogels with Different Toughening Mechanisms and Applications

“…The hydrophilic chains in its network structure are highly entangled and act as sliding links. The tension can be transferred to the micelle crosslinkers during the deformation process of the hydrogel, thereby dissipating energy through the reversible deformation and irreversible separation of the polymer chains and achieving toughening of the hydrogel [ 118 ]. Li et al reported highly stiff and tough protein-based hydrogels constructed by introducing chain entanglements into the hydrogel network made of folded elastomeric proteins, as shown in Figure 4 b.…”

Preparation of diblock copolymer nano-assemblies by ultrasonics assisted ethanol-phase polymerization-induced self-assembly

“…To address these issues, the PISA method was developed. It can directly prepare diblock copolymer nanoparticles with controllable morphology [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , and high concentration (50 wt%), offering the advantages of simplicity, efficiency, and repeatability. With the advancement of PISA, initiation is no longer limited to thermal methods, leading to the emergence of greener and more energy-efficient initiation mechanisms and supportive methods.…”