Conductive hydrogels are a class of composite materials that usually comprise hydrated polymers and conductive materials. Practical application requires the conductive hydrogels to have various properties such as high conductivity, toughness, self-healing, facile processing ability, and so on. Although challenging to have all the above-mentioned properties, a composite material composed of polymer hydrogel with embedded Au nanoparticles (i.e., P(NaSS)/P(VBIm-Cl)/PVA@Au) was found to show the comprehensive properties above in this paper. For example, P(NaSS)/P(VBIm-Cl)/PVA@Au exhibits mechanical and electrical self-healing properties at ambient conditions. In addition, P(NaSS)/P(VBIm-Cl)/PVA@Au is tough and thermoplastic, potentially making it useful for a variety of applications.Keywords: conductive hydrogel; dual network; self-healing; thermoplastic; toughness;

Conductive hydrogels are a class of composite materials that usually comprise hydrated polymers and conductive materials. Practical application requires the conductive hydrogels to have various properties such as high conductivity, toughness, self-healing, facile processing ability, and so on. Although challenging to have all the above-mentioned properties, a composite material composed of polymer hydrogel with embedded Au nanoparticles (i.e., P(NaSS)/P(VBIm-Cl)/PVA@Au) was found to show the comprehensive properties above in this paper. For example, P(NaSS)/P(VBIm-Cl)/PVA@Au exhibits mechanical and electrical self-healing properties at ambient conditions. In addition, P(NaSS)/P(VBIm-Cl)/PVA@Au is tough and thermoplastic, potentially making it useful for a variety of applications.Keywords: conductive hydrogel; dual network; self-healing; thermoplastic; toughness;

A new polymeric hydrogel P(PVIS–AA) based on zwitterionic liquids (1-propyl-3-vinyl imidazole sulfonate) (PVIS) and acrylic acid (AA) was prepared by free-radical polymerization. The resulting three-dimensional (3D) networks can serve as nano-reactors for the production of small size and highly stable palladium nanoparticles by in situ reduction of PdCl62− with sodium borohydride (NaBH4) as a reducing agent. To get enough mechanical strength, ferric (Fe3+) was used to form the second crosslinking. The as-prepared hybrid hydrogel (P(PVIS–AA)/Pd@Fe3+) was successfully confirmed by means of Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), an electrical universal material testing machine, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA), and then tested to catalyze the reduction of 4-nitrophenol. The catalytic results indicate that within 6 min, 4-nitrophenol with an initial concentration of 5 mM can be reduced completely, in addition, the mechanically strengthened P(PVIS–AA)/Pd@Fe3+ hydrogel shows excellent reusability for five successive cycles, with no appreciable decrease in the catalytic effects.

CuO nanowire surfaces with micro/nanometer structures were constructed on a copper substrate by a facile thermal oxidation method, the CuO nanowires have micro/nanometer structures similar to those of the hind wings of water boatmen. The as-fabricated CuO nanowire surface is superhydrophilic, and the water contact angle on it is less than 5°. Modifying the CuO nanowire surface with dodecanethiol (DDT) switched the wettability from superhydrophilic to superhydrophobic with a water contact angle of 154° and a glide angle of 4°. In addition, the original superhydrophilic behavior was regained via annealing at 300 °C due to the desorption of the low surface energy monolayer of DDT. The transition between superhydrophobicity and superhydrophilicity could be switched by alteration of the adsorption/desorption of the DDT monolayer. Compared with the superhydrophilic CuO nanowire surface, the superhydrophobic CuO nanowire surface exhibits better corrosion resistance and self-cleaning properties.

•Copper film with flower-like structure was fabricated by electroless deposition.•Film exhibits superhydrophobicity after being modified by DDT.•Switchable wettability can be controlled by annealing and remodification.•Superhydrophobic copper film has good anticorrosion properties.Reversible surface wetting behaviors between superhydrophobicity and superhydrophilicity is a hot topic research due to its potential applications in engineering. In the present work, a superhydrophilic copper film with flower-like structures was fabricated on zinc plate by a facile method of electroless deposition, and water contact angle on the copper film is 0°. After being modified by dodecanethiol (DDT), the superhydrophilic film was converted to be superhydrophobic with a water contact angle larger than 152° and a gliding angle lower than 5°. Interestingly, the superhydrophobic copper film was switched back to superhydrophilic after being annealed at 300 °C for 30 min and restored to superhydrophobic again after remodification with DDT, and the reversible switch between superhydrophobicity and superhydrophilicity could be repeated several times. Compared with the bare zinc plate and unmodified copper film, the superhydrophobic copper film modified by DDT possesses good anticorrosion properties due to the trapped air in the hierarchical structure of the “flower pits”.

Highly swelling P(2-acrylamido-2-methyl-1-propanesulfonic acid- co-acrylic acid) (P(AMPS-co-AAc)) superabsorbent hydrogel was synthesized in aqueous solution by a simple one-step using glow-discharge electrolysis plasma technique, in which N,N’-methylenebisacrylamide was used as a crosslinking agent. The structure, thermal stability and morphology of P(AMPS-co-AAc) superabsorbent hydrogel were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. A mechanism for synthesis of P(AMPS-co-AAc) superabsorbent hydrogel was proposed. The reaction parameters affecting the equilibrium swelling (i.e., discharge voltage, discharge time, macroscopic temperature of the liquid phase, mass ratio of AMPS to AAc, and content of crosslinker) were systematically optimized to achieve a superabsorbent hydrogel with a maximum swelling capacity. The hydrogel formed which absorbed about 1,685 g H2O/g dry hydrogel of the optimized product was used to study the influence of various pH values and salts solutions (NaCl, KCl, MgCl2, and CaCl2) on the equilibrium swelling. In addition, swelling kinetics in distilled water and on–off switching behavior were preliminarily investigated. The results showed that superabsorbent hydrogel was responsive to the pH and salts.

Silica spheres are used as a template to prepare Ag-coated silica nanospheres through electrostatic interaction, using a technique of homogeneous shaking instead of magnetic stirring. Pre-synthesized spherical Ag nanoparticles are firstly adsorbed onto silica spheres through bifunctional linking molecule, the silane reagent 3-aminopropyltrimethoxysilane, to form thin silver shells. These monodispersed Ag-coated silica nanospheres are assembled onto the glass substrates, which have been functionalized by 3-aminopropyltrimethoxysilane, to form close-packed three-dimensional Ag-coated silica nanosphere arrays by electrostatic interaction. The Ag-coated silica nanospheres were investigated as substrates for surface-enhanced Raman scattering using Rhodamine 6G as a probe molecule, and the enhancement factor of the Raman signal obtained on the Ag-coated silica nanospheres is about 1.74 × 109 for R6G. Compared with pure silver hydrosols, the prepared Ag-coated silica nanospheres have a higher Raman enhancing effect. The hybrid nanosphere substrates can be used as a highly sensitive chemical and biological sensor for Rhodamine 6G dye.Graphical abstractHighlights►A highly active and stable surface-enhanced Raman scattering substrate has been prepared. ►Raman spectra intensity of Rhodamine 6G is enhanced by a factor of 1.74 × 109.►This substrate can be used to determine Rhodamine 6G at very low concentrations.

Well-defined poly (ionic liquid) brushes with tunable wettability are successfully synthesized via nitroxide-mediated radical polymerization. X-ray photoelectron spectroscopy, attenuated total reflection infrared spectroscopy and static water contact angle measurements are used to monitor each step. Ellipsometry, nuclear magnetic resonance (1H and 13C) spectra and gel permeation chromatographic measurements reveal that there is a linear increase in polymer film thickness with polymerization time, indicating that chain growth from the surface is a controlled/“living” polymerization. The surface morphology was measured by atomic force microscopy. Moreover, the surfaces of the poly (ionic liquid) brushes with tunable wettability and reversible switching between hydrophilicity and hydrophobicity can be easily achieved by counteranion exchange.

Novel polyelectrolyte-grafted core-shell organic/inorganic hybrid nanospheres which possess hard backbone of silica nanoparticles and soft shell of cross-linked poly(ionic liquids) (PILs) have been synthesized via a surface-initiated atom transfer radical polymerization (SI-ATRP). After removal of the core templates of the core-shell nanospheres, nearly monodispersed hollow polyelectrolyte nanospheres were obtained. Various characterization techniques including FT-IR, XPS, and TEM were used to characterize the resulting core-shell and hollow polyelectrolyte nanospheres. The results showed that the hollow nanosphere has a hollow core of an average diameter of ca. 200 nm with a shell thickness of ca. 25 nm. The obtained hollow polyelectrolyte nanospheres could be applied in release-control systems.

The synthesis of well-defined poly (ionic liquid) brushes with tunable wettability using surface initiated atom transfer radical polymerization (ATRP) was reported. Various characterization techniques including ellipsometry, static water contact angle measurements, attenuated total reflection infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM) were used to characterize the films for each surface modification step. Kinetic studies revealed a linear increase in polymer film thickness with reaction time, indicating that chain growth from the surface was a controlled process with a “living” characteristic. Furthermore, the surface of poly (ionic liquid) brushes with tunable wettability, reversible switching between hydrophilicity and hydrophobicity can be easily achieved by exchanging their counteranions.

Nd2O3 nanopowders were prepared by a novel sol–gel auto-combustion method using additive agent polyvinyl alcohol. The gel transformed from the aqueous solutions of metal nitrate, citric acid and small quality of polyvinyl alcohol underwent a self-propagation combustion process when ignited and yielded voluminous ashes. These ashes were single phase Nd2O3 powders with a particle size of 20–30 nm. The influences of preparation conditions such as the molar ratio of Nd3+ to citric acid, the amount of additive agent polyvinyl alcohol, the pH value of the reaction system on the formation of the particles have been studied in detail. X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) were used for the sample characterization. It was found that the optimum molar ratio of Nd3+ to citric acid was 1:2, the optimum amount of polyvinyl alcohol was 10% of Nd(NO3)3. In addition, we also studied the catalytic activity of nanometer Nd2O3 and super solid acid SO42−/Nd2O3 in the synthesis of isobutyl acetate.

Magdala Red (MR) binding to protein causes a decrease in the fluorescence intensity of MR at 556 nm. Based on this, a new quantitative determination method for proteins is developed. The linear range of this assay is 0.1–4.0 μg ml−1 of Bovine Serum albumin (BSA). The measurements can be made easily on a common fluorimeter. The reaction between MR and proteins is completed in 1 min, and the fluorescence intensity is stable for at least 2 h. There is little or no interference from amino acids and most metal ions. The proposed method has been applied to the determination of protein in milk powder and soybean milk powder and the results are in agreement with the results by the other methods.