Novel Nanocomposite Hydrogels Consisting of Layered Double Hydroxide with Ultrahigh Tensibility and Hierarchical Porous Structure at Low Inorganic Content

Abstract

A novel type of polymer nanocomposite (NC) hydrogel with extraordinary mechanical properties at low inorganic content is prepared and investigated. The NC hydrogels consist of isethionate-loaded layered double hydroxide/polyacrylamide (LDH-Ise/PAM) - with LDH-Ise being used because of its swelling properties - and no conventional organic crosslinker. The NC hydrogels exhibit an unusual hierarchical porous structure at the micro- and nanometer scales, and their elongation at break can exceed 4000%.

Self-Healable, Tough, and Ultrastretchable Nanocomposite Hydrogels Based on Reversible Polyacrylamide/Montmorillonite Adsorption

“…With increasing clay content, the ε b decreased to ∼9600% for M 50 A (Figure 3f,g). These ε b values are about 2− 10 times higher than other nanocomposite hydrogels based on synthetic clay (Laponite XLG, 18 Laponite XLS, 48 Laponite RDS 19 ), layered double hydroxide (LDH), 21 or graphene oxide (GO) 20 nanosheets, and polymers of NIPAAm, 18 DMAA, 17 and AAm 19−21,48 monomers (Figure 4), although the estimated cross-link densities are close to those in literature. However, the σ b of 100−180 kPa (Figure 3f, h) fell into a medium level among those in literature (Figure 4).…”

“…Therefore, it is reasonable to use the MBAA 0.1 A hydrogel as a control to the M n A hydrogels to investigate the role played by the noncovalent cross-linking in the mechanical properties of hydrogels. It is noted that these estimated cross-link density values are comparable to those of PAAm/Laponite hydrogels by Tong et al 19 and PAAm/LDH hydrogels by Chen et al 21 by using the rubbery elasticity theory. Therefore, as to be seen below, the difference of mechanical properties of hydrogels in this study and those in literature should not be attributed to the cross-link density difference.…”

“…20 Most recently, layered double hydroxide (LDH) nanosheets have been reported to serve as two-dimensional inorganic cross-linkers to generate PAAm/LDH hydrogels with very high extensibility (∼6000%) but low strength (∼30−50 kPa). 21 So far, only a few strong and tough noncovalent hydrogels have been reported to self-heal. Nanocomposite hydrogels could self-heal through chain migration across damaged interface and readsorption to neighboring clay surfaces.…”

Emerging Parallel Dual 2D Composites: Natural Clay Mineral Hybridizing MoS2 and Interfacial Structure

“…[ 7,8 ] These properties have made graphene be one of the most promising materials in the 21st century for supercapacitors, [ 9,10 ] Li-ion batteries, [ 11,12 ] and fuel cell. [ 13,14 ] Apart from graphene, other 2D nanomaterials have also been regarded as attractive materials recently, such as transition-metal dichalcogenides (TMDs), [15][16][17] layered double hydroxides, [18][19][20] transition metal oxide nanosheets, [21][22][23] and graphene analogues. [ 24 ] In addition, a variety of 2D composites with novel structures and exceptional properties were developed for high technology applications.…”

Two-photon polymerization of hydrogels – versatile solutions to fabricate well-defined 3D structures

“…The potential of hydrogels to become useful biomaterials was rst demonstrated in the 1960s when Wichterle and Lim cross-linked hydroxyethyl methacrylate (HEMA). 3 Since then, numerous improvements in structure and properties of hydrogels [4][5][6] have led to their use in cell encapsulation, 7,8 wound healing 9,10 and drug release. [11][12][13][14] The extraordinary properties of hydrogels and associated signicant experimental achievements have attracted the attention of scientic community to these materials.…”