Search

In this investigation, we described a facile preparation of temperature/photo dual sensitive polymers (PGABs) by Ugi four-component polymerization (Ugi-4CP) at room temperature in “one-pot” method using glutaraldehyde, 4-amido-azobenzene, t-butyl isocyanide and carboxyl-end-capped polyethylene glycols (S-PEG) as monomers. PGABs were found to be reversibly sensitive to the temperature in salt solution, and their lower critical solution temperatures (LCST) can be tuned to the range of 17.2–68.4 °C by changing the structure of PGABs, sort and concentration of salt. The configuration transition of PGABs between cis-form and trans-form was reversibly induced by the alternating radiation at 365 and 254 nm. The rate and conversion of isomerization showed a remarkable dependence on the chemical structure of PGAB. By the photosensitivity, the LCST of PGAB-800 is further regulated in 1.0 °C change because of the hydrophilicity difference of cis-trans-azobenzene moiety. Through the combination of the thermosensitivity and photosensitivity, the particles of PGABs with nano/μm dimension were successfully controlled by the light radiation and temperature change.

Three-dimensional (3D) nanostructured conducting polymer hydrogels represent a group of high-performance electrochemical energy-storage materials. Here, we demonstrate a molecular self-assembly approach toward controlled synthesis of nanostructured polypyrrole (PPy) conducting hydrogels, which was "cross-linked" by a conjugated dopant molecule trypan blue (TB) to form a 3D network with controlled morphology. The protonated TB by ion bonding aligns the free sulfonic acid groups into a certain spatial structure. The sulfonic acid group and the PPy chain are arranged by a self-sorting mechanism to form a PPy nanofiber structure by electrostatic interaction and hydrogen bonding. It is found that PPy hydrogels doped with varying dopant concentrations and changing dopant molecules exhibited controllable morphology and tunable electrochemical properties. In addition, the conjugated TB dopants promoted interchain charge transport, resulting in higher electrical conductivity (3.3 S/cm) and pseudocapacitance for the TB-doped PPy, compared with PPy synthesized without TB. When used as supercapacitor electrodes, the TB-doped PPy hydrogel reaches maximal specific capacitance of 649 F/g at the current density 1 A/g. The result shows that PPy nanostructured hydrogels can be tuned for potential applications in next-generation energy-storage materials.

We reported a facile self-generated sacrificial template method for fabricating mesoporous three dimension NiCo2O4/graphene electrode material. Nickel, cobalt, and zinc ions dissolved in ethylene glycol reacted with potassium hydroxide solution to co-deposit onto graphene at 140 °C under atmospheric environment. With further addition of potassium hydroxide, zinc hydroxide as a self-generated sacrificial template was dissolved in situ, leading to the formation of mesoporous morphology. Structure and morphology characteristics were determined by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and N2 adsorption experiments. Electrochemical properties were analyzed by AC impedance spectroscopy, cycling voltammetry, and charge/discharge test in 2 M KOH. Results showed that the as—prepared NiCo2O4/graphene electrode possessed a large specific surface area of 281.4 m2 g−1, an ultrahigh specific capacity of 1024.99 and 662.12 C g−1 at current density of 1 and 50 A g−1 respectively, and a long-term cycling life of 10,000 charge/discharge tests.

A facile synthesis approach was successfully developed to synthesize mesoporous NiCo2S4 in ethylene glycol. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and N2 adsorption–desorption experiment were conducted to examine the morphology and microstructure of the as-prepared NiCo2S4. Furthermore, electrochemical measurements, including cyclic voltammetry, galvanostatic charge–discharge tests, and electrochemical impedance spectroscopy, were carried out in a three-electrode system to evaluate the electrochemical properties of the mesoporous NiCo2S4. The as-prepared NiCo2S4 possessed a high specific surface area of 223.6 m2 g−1 with a high specific capacity of 406 C g−1 at 0.5 A g−1. In addition, only a 6.3 % loss of specific capacity was observed at 5 A g−1 after 20,000 GCD cycles, suggesting a long life cycle.

In this paper, a series of monomers (M1-M7) were facilely synthesized by Passerini reaction and the subsequent in-situ polymerization led to the formation of the conductive poly(indole/thiophene)s (P1-P7). Among P1-P7, it was found through the comparison that P7-P with a higher conjugated system exhibits an outstanding specific capacitance of 1170 F g−1 (scan rate 1 mV s−1), power density of 2614.4 W kg−1 and energy density of 56.5 Wh kg−1 (5 A g−1). The capacitance performance of P7-P complexed with Fe3+ system is further increased by 130 F g−1 because of the redox reaction of Fe3+. Using the chronoamperometry, the minimum detection limit of polymer P7-P for Fe3+ is 3 × 10−5 M. In summary, the facile synthesis of the conductive poly(indole/thiophene) polymers, their excellent energy storage and Fe3+ detection performance, open an opportunity for functional polymers in the energy storage and sensor applications.