Facile preparation and electrochemical characterization of self-assembled core-shell diamond-polypyrrole nanocomposites

In-Situ Oxidative Polymerization of Pyrrole Composited with Cellulose Nanocrystal by Reactive Ink-Jet Printing on Fiber Substrates

A simple and novel method for the deposition of polypyrrole (PPy) and cellulose nanocrystal (CNC) composites on different fiber substrates by reactive ink-jet printing was proposed. PPy/CNCs composites were successfully prepared, and the surface resistance of conductive layer deposited on different fiber substrates is the least when the monomer concentration is 0.6 M. PPy/CNCs were deposited on polyethylene terephthalate (PET) to form a conductive layer by adding polyvinyl alcohol (PVA), and the optimum sintering temperature is 100 °C (monomer/PVA ratio 4.0, conductivity 0.769 S cm⁻¹). The PPy/CNCs conductive layer deposited on the paper has the lowest surface resistance and the best adhesion, and the surface resistance of PPy/CNCs conductive layer decreases first and then increases with the increase of sulfonate concentration. Moreover, the volume of anion in sulfonate will affect the arrangement and aggregation of PPy molecular chain in composite materials. Appropriate sulfonate doping can improve the conductivity and stability of conductive paper, and the maximum conductivity is 0.813 S cm⁻¹. Three devices based on PPy/CNCs conductive paper were proposed and fabricated. Therefore, this ink-jet printing provides a new method for the preparation of conductive materials, sensors, energy storage and electromagnetic shielding, etc.

Selective Nonenzymatic Amperometric Detection of Lactic Acid in Human Sweat Utilizing a Multi-Walled Carbon Nanotube (MWCNT)-Polypyrrole Core-Shell Nanowire

Lactic acid plays an important role as a biochemical indicator for sports medicine and clinical diagnosis. The detection of lactic acid in sweat is a promising technique without any intrusive inconvenience or risk of infection. In this study, we present a selective nonenzymatic amperometric detection method for lactic acid in human sweat utilizing a multi-wall carbon nanotube (MWCNT)-polypyrrole core-shell nanowire. Because polypyrrole is a p-type conducting polymer, onto which anions are exclusively doped, leading to charge transfer, it offers selective detection for lactate anions at a specific potential, while being inert to the neutral and cationic species contained in human sweat. A chronoamperometric study reveals good sensing performance for lactic acid with a high sensitivity of 2.9 μA mM⁻¹ cm⁻² and detection limit of 51 μM. Furthermore, the MWCNT-polypyrrole nanowire exhibits excellent selectivity for lactic acid over interfering species, such as sodium chloride, glucose, urea, and riboflavin, which coexist with lactic acid in sweat. Finally, a nonenzymatic amperometric sensor for the selective detection of lactic acid in human sweat is demonstrated on commercial flexible electrodes. The results demonstrate the potential applications of the MWCNT-polypyrrole core-shell nanowire as a nonenzymatic amperometric lactate sensor.

Highly flexible reduced graphene oxide@polypyrrole-polyethylene glycol foam for supercapacitors

A flexible and free-standing 3D reduced graphene oxide@polypyrrole–polyethylene glycol (RGO@PPy–PEG) foam was developed for wearable supercapacitors. The device was fabricated sequentially, beginning with the electrodeposition of PPy in the presence of a PEG–borate on a sacrificial Ni foam template, followed by a subsequent GO wrapping and chemical reduction process. The 3D RGO@PPy–PEG foam electrode showed excellent electrochemical properties with a large specific capacitance of 415 F g⁻¹ and excellent long-term stability (96% capacitance retention after 8000 charge–discharge cycles) in a three electrode configuration. An assembled (two-electrode configuration) symmetric supercapacitor using RGO@PPy–PEG electrodes exhibited a remarkable specific capacitance of 1019 mF cm⁻² at 2 mV s⁻¹ and 95% capacitance retention over 4000 cycles. The device exhibits extraordinary mechanical flexibility and showed negligable capacitance loss during or after 1000 bending cycles, highlighting its great potential in wearable energy devices.

A flexible and free-standing 3D reduced graphene oxide@polypyrrole–polyethylene glycol (RGO@PPy–PEG) foam was developed for wearable supercapacitors.

Zinc oxide-decorated polypyrrole/chitosan bionanocomposites with enhanced photocatalytic, antibacterial and anticancer performance

A bio-nanocomposite matrix of polypyrrole grafted ZnO/chitosan (Ppy/C/Z) was synthesized via the in situ polymerization of pyrrole with different weight fractions of ZnO. Incorporation of ZnO nanoparticles with polypyrrole enhances the photocatalytic, antibacterial as well as cytotoxic properties of the resultant composite. Characterizations of the synthesized product were performed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal analysis (TGA and DTA). Surface morphology and particle size were determined by SEM and TEM. The elemental composition of the material was studied by EDX coupled with SEM. Electrochemical surface area was calculated from electrochemical double layer capacitance (EDLC) measurements using cyclic voltammetry. The photocatalytic activity of the composite material was tested by monitoring the degradation of reactive orange-16 (RO-16), Coomassie Brilliant Blue R-250 (CBB-R-250) and Methylene Blue (MB) dyes and the composite was found to be an effective catalyst in the presence of a UV light source. Various scavengers were used to detect the reactive species involved in the photocatalytic process. Furthermore, the stability of the photocatalyst was assessed by recycling experiments. Moreover, the Ppy/C/Z bio-nanocomposite shows potential application with anti-bacterial and anti-cancer activity against Gram-positive and Gram-negative bacterial pathogens and human cancer cell lines (HeLa and MCF-7). The experimental data confirm that the bio-nanocomposite of Ppy/C/Z showed excellent anti-bacterial and anti-cancer activity as compared to a pristine polypyrrole and chitosan formulation (Ppy/C). The apoptosis data with varying concentrations of Ppy/C/Z reveal the remarkable activity against these cancer cell lines.

Bio-nanocomposites were synthesized via grafting polypyrrole/ZnO onto chitosan chain for the photodegradation of organic pollutants and biomedical applications.