Ultrastretchable, Adhesive, and Antibacterial Hydrogel with Robust Spinnability for Manufacturing Strong Hydrogel Micro/Nanofibers

Abstract

underway to construct hydrogel materials into different shapes such as 3D, [5] 2D, [6] or fiber-like configurations, [7] wherein hydrogel fibers as a novel type of materials cast great impact on our daily life, ranging from smart textile, [8] conductor to functional reinforcements. [9] Compared with 3D and 2D hydrogels, fiber-like hydrogel, also known as 1D hydrogel fiber, always possess smaller cross-sectional areas, [10] which means such thin hydrogel fibers would bear more significant tensile force under the same load, leading to a higher standard on the mechanical properties for engineering 1D hydrogel fibers.With the synergistic effect of covalent and reversible bonds including hydrogen bonds, [11] hydrophobic interactions, [12] ionic bonds, and host-guest interactions, [13] a variety of hydrogel fibers with great mechanical properties have been developed, such as artificial spider silk with twisted core-sheath hydrogel fibers (tensile strength of 895 MPa and strain of 44.3%), [14] ultrastretchable fibers (tensile strength of 5.6 MPa and strain of 1180%), [9] and supramolecular fibers (tensile strength of 193 MPa and strain of 36%). [15] Despite their excellent mechanical properties, those hydrogel fibers are fabricated by manual drawing from the hydrogel, limiting their practical applications where scaled-up manufacture of fibers is required.To satisfy the demand of scaled-up production, the eligible hydrogel fibers are anticipated to be manufactured on a large scale via spinning process, including electrospinning, [16] extrusion spinning, [17] microfluidic or draw-spinning process. [18] For example, Ju et al. developed a hydrogel microfiber based on a continuous draw-spinning process, and the resulting fibers exhibited tensile stress of 1.4 MPa. [19] Song et al. spun a transparent hydrogel fiber possessing tensile stress of 200 kPa. [20] It should be noted that, as for spinning those hydrogel fibers, relatively low crosslinking density is often essential to a spinning solution due to the large deformation required during the spinning process and the requirements for spinning long and uniform hydrogel fibers, [19] which, in turn, leads to unsatisfied mechanical properties of the final spun hydrogel fibers.

Ultrafast Fabrication of Lignin-Encapsulated Silica Nanoparticles Reinforced Conductive Hydrogels with High Elasticity and Self-Adhesion for Strain Sensors

“…37−39 Moreover, lignin not only possesses the characteristics of antiultraviolet activity, antibacterial property, and good biocompatibility but also can serve as a reducing agent, which can form dynamic redox reactions with metal ions (e.g., Ag + , Cu 2+ , Zn 2+ , Ni 3+ , and Fe 3+ ) to facilely fabricate multifunctional hydrogels at room temperature. 11,38,40,41 For instance, Lu et al 33 developed a lignin−Ag NPs dynamic redox system to rapidly fabricate the adhesive and tough hydrogels for simultaneously achieving long-term (28 days) self-adhesion. However, lignin suffers from poor water solubility, which precludes its application in the hydrogels to replace the water-soluble polyphenols.…”

Strong and Tough Conductive Organo‐Hydrogels via Freeze‐Casting Assisted Solution Substitution

“…[14,15] Due to the anisotropic growth kinetics of ice crystals, freeze-cast materials have anisotropic microscopic structures similar to human muscles, tendons, and ligaments, and exhibit excellent mechanical properties. [9] At the sub-micron scale, solution-induced aggregation, [9,16] directed assembly, [17] and electrostatic spinning [18] have been investigated. Solution-induced aggregation is the most straightforward where the hydrogel is immersed in a solution for a period to introduce hydrophobic cross-linking and crystalline domains.…”

An Overview on Recent Progress of the Hydrogels: From Material Resources, Properties, to Functional Applications

“…[46] Additionally, by reducing diffusion of matrix metal precursors in the solution, metal nanoparticles can also be loaded in the preparation of hydrogels. [47][48][49] Hydrogel nanocomposite materials consists of polymer hydrogels and organic nanoparticles embedded in the hydrogel matrixes, [48,[50][51][52][53] which have attracted great attention owing to their distinctive inorganic and organic hybrid structures and the excellent mechanical properties in aspects of elasticity, [54,55] toughness, [56][57][58] viscosity, [59,60] and so on. In the process of hydrogels (the conversion of low viscosity solution to hydrogels), technologies such as microfluidic are allowed to prepare hydrogels with arbitrary geometry.…”