Synthesis and characterization of nanostructured PZT encapsulated PVA–PAA hydrogel

Conductive Tough Hydrogels with a Staggered Ion-Coordinating Structure for High Self-Recovery Rate

Conductive hydrogels are attracting increasing attention owing to their great potential for applications in flexible devices. For practical use, these high-water-content materials should not only show good conductivity but also be strong, stretchable, tough, and elastic. Herein, we describe a class of novel conductive tough hydrogels based on strong staggered Fe³⁺-carboxyl coordinating interactions. They are made from copolymers of acrylamide and N-acryloyl glutamic acid, a bidentate-based comonomer. The design of the staggered structure of Fe³⁺ and bidentate units is expected to enable energy dissipation and also results in a synergetic effect of two binding sites for fast self-recovery. We demonstrate that the equilibrated hydrogels with a water content of 53 wt % exhibit superior mechanical properties (e.g., highest tensile strength, 12.1 MPa; Young's modulus, 36.1 MPa; work of extension, 42.1 MJ m^-3; fracture energy, 10,691 J m^-2; compressive strength, 65.1 MPa at 98% strain without a macroscopic fracture) compared to the ion-coordinated hydrogels reported to date, including elasticity at small strain, fast self-recoverability at room temperature (∼25 °C), a high dielectric constant (k = 341-1395 at 100 kHz), and good electrical conductivity (0.0018-0.024 S cm^-1). Given their extraordinary overall characteristics, we envision their potential applications in flexible electronic devices.

Ultrasound assisted synthesis of polyacrylic acid-nanoclay nanocomposite and its application in sonosorption studies of malachite green dye

Synthesis of nanoclay nanocomposite has been undertaken by using polyacryalic acid (PAA) in aqueous medium and ultrasound environment and its application in dye removal has been investigated. The synthesized product was characterized by using FTIR and XRD techniques. The sonosorption capacity of the product namely PAA-nanoclay composite was determined by choosing malachite green (MG) dye as a model pollutant. The effects of various parameters such as nanocomposite loading, pH, various process conditions etc. have been studied. On comparing the results obtained with that of nanoclay as an adsorbent, it was found for an initial concentration of 500mg/l, the PAA-nanoclay nanocomposite exhibited higher percentage of pollutant removal (68%) and for nanoclay it was 54%. The adsorption data has been correlated using Langmuir and Freundlich models. The fit of the Freundlich isotherm model was found to be good in the entire range of concentration for the experimental sorption data obtained on the nanoclay nanocomposite. A plausible reaction mechanism for use of PAA-nanoclay nanocomposite as an adsorbent is also proposed.