New composite thixotropic hydrogel composed of a polymer hydrogelator and a nanosheet

Abstract

A composite gel composed of a water-soluble aromatic polyamide hydrogelator and the nanosheet Laponite®, a synthetic layered silicate, was produced and found to exhibit thixotropic behaviour. Whereas the composite gel contains the gelator at the same concentration as the molecular gel made by the gelator only, the composite gel becomes a softer thixotropic gel compared to the molecular gel made by the gelator only. The reason for this could be that bundles of polymer gelator may be loosened and the density of the polymer network increased in the presence of Laponite.

Polymeric Hydrogelator-Based Molecular Gels Containing Polyaniline/Phosphoric Acid Systems

“…By increasing the stress on the gels ( Figure 2 b), G′ and G″ demonstrated the transition from the gel state (G′ > G″) to the sol state (G′ < G″) over the intersection of G′ and G″. The results of the composite hydrogel also confirmed the gel state and the formation of a softer and more tenacious hydrogel than the corresponding NaPPDT hydrogel, evidenced by the shift in the value and cross point of G′ and G″, as also indicated for the other mixed composite hydrogels composed of LAPONITE ® [ 53 ] or polyaniline/water-soluble polymer complex with NaPPDT [ 54 ].…”

“…To develop novel gel materials that are expected to have an affinity with living organisms and that can mediate electrical signals, this study aimed to generate conductive molecular hydrogels by compositing hydrophilic conductive polymers through mixing, using a polymeric hydrogelator as a matrix to form the hydrogel material. Poly(sodium-3–sulfo-p-phenyleneterephthalamide) ( NaPPDT ) [ 52 ] was selected as a polymer hydrogelator ( Scheme 1 ), as it is capable of creating various composite materials, such as LAPONITE ® [ 53 ], a water-soluble silicate, and polyaniline/water-soluble polymer polyion complexes [ 54 ], with better gel properties. In this study, a hydrophilic conductive polymer complexed with phosphoric acid ( PAPA , Scheme 1 ) was selected as the hydrophilic conductive polymer, as it enabled us to obtain water-soluble conductive polyaniline polymerized from aqueous aniline phosphoric acid solutions through oxidation.…”

Physical and Chemical Factors Influencing the Printability of Hydrogel-based Extrusion Bioinks

“…The main modulator of this rheological property involves dynamic interactions of various physical bonds between the surface of nanomaterials and the hydrogels. Recently, various nanomaterials, including calcium carbon nanotubes (CNTs), − graphene oxide (GO) nanosheets, , calcium carbonate, Laponites, , silica nanoparticles, and gold and silver nanoparticles, − are employed in either unmodified or modified state. The rational combination of these nanomaterials with native or functionally modified polymers may also provide a deep understanding regarding a wide variety of choices in combinations of chemical species for 3D printable hydrogel bioinks.…”

Creation of Polymer Hydrogelator/Poly(Vinyl Alcohol) Composite Molecular Hydrogel Materials

“…This qualitative improvement in the composite gel network due to mixing may be the reason for the improved mechanical properties as measured by dynamic viscoelasticity described above. Although there is a concern that observation of such dried xerogel samples will show artefacts not present in the original gel-like samples due to shape changes during the drying process, it is thought that even if there are changes during the drying process, it is certain that the components have become smaller due to the mixing process as shown in our previous studies [ 19 , 20 , 21 ].…”