Surfactant-assisted synthesis of a transparent ionic nanocomposite hydrogel

A facile approach to prepare strong poly(acrylic acid)/LAPONITE® ionic nanocomposite hydrogels at high clay concentrations

“…Besides, direct addition of even a small amount of ionic monomer into the LAPONITE® dispersion induced gelation and the clay dispersion quickly became subsided and opaque due to the decrease of the Debye distance for the electrostatic repulsion. 13,[23][24][25][26]29,[32][33][34] So it has been challenging to synthesize ionic NC hydrogels at high LAPONITE® concentrations.…”

“…Numerous attempts to overcome the problem have been reported thus far, in which two main strategies were developed: (1) using nonionic monomers to pre-adsorb onto the surface of LAPONITE® before further polymerization of ionic monomers; 13,[23][24][25][26][27][28] (2) choosing specic ionic monomers to realize good dispersion of LAPONITE®. [29][30][31] In our previous work, transparent ionic NC hydrogels crosslinked by LAPONITE® XLG were successfully synthesized via the in situ free radical polymerization of AA with the assistance of 2acrylamido-2-methylpropanesulphonic acid (AMPS) 29 and sodium dodecyl sulfate (SDS), 32 and the ultimate tensile strengths could reach 189 kPa and 162 kPa, respectively. The addition of AMPS or SDS can successfully avoid the aggregation of LAPONITE® in the ionic AA monomer.…”

Temperature sensitive hydrogels cross-linked by magnetic LAPONITE® RD®: effects of particle magnetization

“…23 The shape anisotropy of Lap nanoparticles and heterogeneity of surface charge distribution can lead to complex self-assembly and networking inside such systems. 24 Lap-doped hydrogels based on acrylamide, 25 acrylic acid, 26 N-isopropylacrylamide, 27 and dimethyl-acrylamide 28 have been already synthesized. As examples, Lap was used as an effective cross-linker for preparing the poly(N,N-dimethylaminoethyl methacrylate) based pH and temperature double-sensitive hydrogels with homogeneous distribution of the cross-link points along the gels.…”

Electric field-induced gradient strength in nanocomposite hydrogel through gradient crosslinking of clay

“…21,22 When dispersed in deionized water, LAPONITE s forms aggregates with house-of-cards structures due to the negative surface charges and positive charges on the rim of LAPONITE s . 22,[24][25][26] However, the introduction of electric field would be useful for scattering LAPONITE s and reducing its enrichment in aqueous dispersions. 22,[24][25][26] However, the introduction of electric field would be useful for scattering LAPONITE s and reducing its enrichment in aqueous dispersions.…”

“…23 Thus, it is hard to prepare NC hydrogels in the presence of ionic monomers or high concentrations of LAPONITE s due to the aggregation and gelation of LAPONITE s . 22,[24][25][26] However, the introduction of electric field would be useful for scattering LAPONITE s and reducing its enrichment in aqueous dispersions. This specific characteristic was explored for the highly ordered arrangement of clay in direct-current (DC) electric field.…”