Super-tough and thermo-healable hydrogel – promising for shape-memory absorbent fiber

Abstract

Super-tough and highly squeezable hydrogel by a one-step polymerization shows ultra extendability and healability and leads to a shape-memory absorbent fiber.

Extremely strong and tough hydrogels as prospective candidates for tissue repair – A review

“…[155] Carrageenan, a partially sulfated polysaccharide obtained from red seaweeds, is composed by β-D-galactose and 3,6-anhydro-α-Dgalactose units. [51] According with the degree of sulfation, three kinds of carrageenan can be obtained, namely, kappa-carrageenan (KC) with one sulfate per disaccharide, iota-carrageenan (IC) with two sulfates per disaccharide and lambda-carrageenan (LC) which is highly sulfated.…”

“…[126] Taking advantage of the previously stated methodologies to synthesize strong and tough hydrogels, researchers have engineered a variety of systems to meet the complex biological and mechanical requirements of TE. Undoubtedly, among all the methods, the DN approach affords the highest versatility in terms of composition and resulting properties, and therefore, it has been extensively employed by combining, for instance, bacterial-cellulose with gelatin, alginate, carrageenan or gellan-gum [128]; gellan-gum derivatives with gelatin [137,139] or poly(acrylamide) [135,139]; chitin with poly(vinyl alcohol) [144]; alginate derivatives with poly(vinyl alcohol) [152] or poly(acrylamide) [71,151]; agar with poly(acrylamide) [154]; carrageenan with poly(acrylamide) [155]; acid hyaluronic derivatives with poly(dimethylacrylamide) [168]; and chondroitin sulfate with poly(acrylamide) [160], resulting in structures with improved strength and toughness which is of outmost importance for tissue repair. More hydrogels systems were already developed combining other natural-origin materials.…”

A review of shape memory polymers bearing reversible binding groups

“…The ability to instill shape memory characteristics using ionic interactions is not limited to hydrophobic polymers as evidenced by recent reports of ion containing shape memory hydrogels (SMH) . For example, a dual‐responsive SMH based on acrylamide (AM), acrylic acid (AA), and a low concentration (1.5 mol %) of cationic surfmer (Dimethylhexadecyl[2(dimethylamino)ethylmethacrylate]ammonium bromide) (C16DMAEMA) was recently reported .…”

“…These materials were also formable upon heating, thus, allowing for reprogramming of the SMH's permanent shape. In another example, super tough double network (DN) hydrogels based on a crosslinked poly(acrylamide) (PAAm) and ionically crosslinked carrageenan were shown to exhibit high extensibility (20× their initial length) and high fracture energy (∼9500 J/m 2 ) . The high toughness is attributed to the presence of ionic crosslinks that act as sacrificial bonds breaking and dissipating energy thereby preserving the covalent network.…”

Ultrastretchable, Super Tough, and Rapidly Recoverable Nanocomposite Double‐Network Hydrogels by Dual Physically Hydrogen Bond and Vinyl‐Functionalized Silica Nanoparticles Macro‐Crosslinking

“…Traditional DN hydrogels with two irreversible chemically crosslinked networks cannot be repaired or recovered from damage and fatigue . A number of hybrid crosslinked DN gels are developed with the physically crosslinked first network such as agar or gelatin by hydrogen bonds, and polysaccharide by metal ions . The reversible noncovalent first physical networks work as new sacrificial networks to provide some extent recovery of the structure and mechanical properties of DN gels.…”