"Honeycomb" Photothermal Lubricated Porous Foam with Low-Temperature, Weak-Light, Anti-Icing/Deicing, and Long-Lasting Lubrication Properties

The prevalence of icing in nature has become a significant threat to human work and life, prompting the development of more energy-efficient active/passive combination anti-icing/deicing technologies. In order to overcome the disadvantage of the poor durability of superhydrophobic surfaces, lubricated surfaces inspired by nepenthes have been preferred. In this study, a paraffin and silicone oil-infused photothermal foam (PSIPF) with excellent overall performance was prepared using polypyrrole (PPy) as a photothermal conversion material, a mixture of silicone oil and paraffin as a lubricating fluid, and melamine foam (MF) as a carrier. The surface adhesive strength is less than 20 kPa at -20 °C, the melting time is only 1018 s at an irradiance of 200 W/m2 and -20 °C (0.2 sun), and surface droplets do not freeze within 1 h at -10 °C. Furthermore, the surface exhibits excellent mechanical durability and stability, maintaining optimal lubrication properties following repeated cycles of icing/deicing, water rinsing, and immersion for 2 days in acid and alkaline conditions. This photothermal lubricated surface with excellent anti-icing/deicing properties at low temperatures and in weak-light environments provides a wider range of applications for equipment at high latitudes and high altitudes.

Fabrication of Textile-Based Flexible Supercapacitor with a Textile Dye on Polyaniline-Based Composite Electrode for Enhanced Energy Storage

Polyaniline (PANI) is a promising conductive polymer for use in energy storage applications. Here, a one-step hydrothermal method of PANI polymerization on carbon felt electrode was synthesized using an azo dye, a bisulfonated dichloro anionic dye molecule to enhance an efficient textile-based flexible supercapacitor electrode material for energy storage applications. The electrode material synthesized at concentration of 2 mM AY17 exhibits 814.1 F g-1 at the scan rate of 5 mV s-1 with multiwall carbon nanotubes (MWCNTs). Due to electrostatic interaction with the polymer, the presence of high electronegativity Cl atoms in the dye molecule significantly improves the PANI structure's electron donor/acceptor properties. A symmetric supercapacitor exhibits an energy density of 11.7 W h kg−1 at a power density of 300 W kg−1, and it is 4.5 W h kg−1 at 1800 W kg−1 in 3.0 M KCl aqueous electrolyte. The capacitance retention performance value of the symmetric supercapacitor exhibited 81.76% after 2500 cycles.

Simple Low Temperature Technique to Synthesize Sillenite Bismuth Ferrite with Promising Photocatalytic Performance

Sillenite-type members of the bismuth ferrite family have demonstrated outstanding potential as novel photocatalysts in environmental remediation such as organic pollutant degradation. This investigation has developed a low temperature one-step hydrothermal technique to fabricate sillenite bismuth ferrite Bi₂₅FeO₄₀ (S-BFO) via co-substitution of 10% Gd and 10% Cr in Bi and Fe sites of BiFeO₃, respectively, by tuning hydrothermal reaction temperatures. Rietveld refined X-ray diffraction patterns of the as-synthesized powder materials revealed the formation of S-BFO at a reaction temperature of 120-160 °C. A further increase in the reaction temperature destroyed the desired sillenite structure. With the increase in the reaction temperature from 120 to 160 °C, the morphology of S-BFO gradually changed from irregular shape to spherical powder nanomaterials. The high-resolution TEM imaging demonstrated the polycrystalline nature of the S-BFO(160) nanopowders synthesized at 160 °C. The as-synthesized samples exhibited considerably high absorbance in the visible region of the solar spectrum, with the lowest band gap of 1.76 eV for the sample S-BFO(160). Interestingly, S-BFO(160) exhibited the highest photocatalytic performance under solar irradiation, toward the degradation of rhodamine B and methylene blue dyes owing to homogeneous phase distribution, regular powder-like morphology, lowest band gap, and quenching of electron-hole pair recombination. The photodegradation of a colorless organic pollutant (ciprofloxacin) was also examined to ensure that the degradation is photocatalytic and not dye-sensitized. In summary, Gd and Cr co-doping have proven to be a compelling energy-saving and low-cost approach for the formulation of sillenite-phase bismuth ferrite with promising photocatalytic activity.

Biomimetic Synthesis of PANI/Graphitic Oxidized Carbon Nitride for Supercapacitor Applications

Polyaniline (PANI) composites have gained momentum as supercapacitive materials due to their high energy density and power density. However, some drawbacks in their performance remain, such as the low stability after hundreds of charge-discharge cycles and limitations in the synthesis scalability. Herein, we report for the first time PANI-Graphitic oxidized carbon nitride composites as potential supercapacitor material. The biomimetic polymerization of aniline assisted by hematin, supported by phosphorous and oxygen-modified carbon nitrides (g-POCN and g-OCN, respectively), achieved up to 89% yield. The obtained PAI/g-POCN and PANI/g-OCN show enhanced electrochemical properties, such as conductivity of up to 0.0375 S/cm, specific capacitances (C_s) of up to 294 F/g (at high current densities, 5 A/g) and a stable operation after 500 charge-discharge cycles (at 3 A/g). In contrast, the biomimetic synthesis of Free PANI, assisted by stabilized hematin in cosolvents, exhibited lower performance properties (65%). Due to their structural differences, the electrochemical properties of Free PANI (conductivity of 0.0045 S/cm and C_s of up to 82 F/g at 5 A/g) were lower than those of nanostructured PANI/g-POCN and g-OCN supports, which provide stability and improve the properties of biomimetically synthesized PANI. This work reveals the biomimetic synthesis of PANI, assisted by hematin supported by modified carbon nitrides, as a promising strategy to produce nanostructured supercapacitors with high performance.

Antimicrobial Properties of the Polyaniline Composites against Pseudomonas aeruginosa and Klebsiella pneumoniae

CuO, TiO2, or SiO2 was decorated on polyaniline (PANI) by a sonochemical method, and their antimicrobial properties were investigated for two common Gram-negative pathogens: Pseudomonas aeruginosa (PA) and Klebsiella pneumoniae (KP). Without PANI, CuO, TiO2, or SiO2 with a concentration of 220 µg/mL exhibited no antimicrobial activities. In contrast, PANI-CuO and PANI-TiO2 (1 mg/mL, each) completely suppressed the PA growth after 6 h of exposure, compared to 12 h for the PANI-SiO2 at the same concentration. The damage caused by PANI-SiO2 to KP was less effective, compared to that of PANI-TiO2 with the eradication time of 12 h versus 6 h, respectively. This bacterium was not affected by PANI-CuO. All the composites bind tightly to the negative groups of bacteria cell walls to compromise their regular activities, leading to the damage of the cell wall envelope and eventual cell lysis.

Novel polymerization of aniline and pyrrole by carbon dots

This work reports on the synthesis of polymers (polyaniline, polypyrrole, and co-polymerization of polyaniline and polypyrrole) from monomers using carbon dots and UV light as initiators.