Synthesis of Conducting Polypyrrole-Titanium Oxide Nanocomposite: Study of Structural, Optical and Electrical Properties

Highly sensitive electrochemical biosensor for MUC1 detection based on DNA-functionalized CdTe quantum dots as signal enhancers

In this paper, an electrochemical biosensor based on a cadmium telluride/polypyrrole (CdTe/PPy) nanocomposite was developed for the detection of MUC1 with high selectivity and sensitivity. Results indicate that the CdTe/PPy nanocomposite is modified on the surface of the glassy carbon electrode (GCE), which affords a large surface area for immobilizing cap-DNA, ensuring its high selectivity and sensitivity. Next, CdTe-linked sig-DNA (MUC1 aptamer) was introduced, allowing the MUC1 aptamer to hybridize with cap-DNA. CdTe is a signal amplification element used to generate a differential pulse voltammetry (DPV) signal. Conceivably, target MUC1 detection was based on current signal change due to concentration change in the signal amplification element CdTe. In the presence of MUC1, the MUC1 aptamer specifically binds to MUC1, resulting in the release of CdTe-sig-DNA from the electrode surface and a decrease in peak current. Under optimized experimental conditions, the electrochemical biosensor is highly selective, sensitive, stable, and reproducible for MUC1 ranging from 0.1 nM to 100 nM with a detection limit of 0.05 nM (S/N = 3). Therefore, the electrochemical biosensor has potential applications in medical disease diagnosis.

Ameliorated optical, luminescent and thermo-chemical features of polymer derived PPy-SnO2 nanocomposite as efficient emissive layer material (EML)

PPy-SnO2 (PS) nanocomposite was synthesized with varying doses of SnO2 through in-situ oxidative polymerization technique. Morphological study was performed through FESEM analysis. Particle size of the 15% PS nanocomposite was estimated in the 13-35 nm range by XRD analysis. Elemental presence and its deconvoluted states in the 15% PS nanocomposite were confirmed by XPS analysis. Optical band gap for optimized 15% PS was calculated ∼1.83 eV. PL intensity increases with increase in the concentration of SnO2. Its value was found highest for 15% PS laid in the light blue region (close to white light). CIE color coordinate study of the nanocomposites elucidated that optimized 15% PS could be used as efficient emissive layer material for WLED application. A comparative TGA study of the PPy and 15% PS illustrated that optimized 15% PS nanocomposite proved to have better thermal stability.

Multifunctional screen-printed films using polymer nanocomposite based on PPy/TiO2: conductive, photocatalytic, self-cleaning and antibacterial functionalities

In this work, two electrically conductive samples based on polypyrrole (PPy) and (PPy/TiO₂) were synthesized via mini-emulsion polymerization. Synthesized samples were used as functional fillers to formulate two different screen-printing pastes (pastes A and B) to obtain the multi-purpose printed films with excellent properties, including electrical conductivity, antibacterial, photocatalytic activity, and self-cleaning. The surface tension, pH, and conductivity measurements validated the acceptable features of the produced pastes. Because of the shear-thinning behavior and viscosity buildup properties of the produced pastes, rheological investigations confirmed their potential for screen-printing. According to I–V test results, the optimum sintering temperature was chosen as a function of electrical conductivity, and the properties of the printed patterns were investigated by varying the printing sequences as 3, 6, and 9 times and sintered at the optimum temperature (90 °C). The contact angle of water on the optimum sample printed by Paste B was ca. 127° and relatively higher than the counterpart printed by Paste A which verified the superiority of the self-cleaning properties of the printed films with latter paste over the former. The photocatalytic studies concerning the degradation of methylene blue showed that the removal percentage of ca. 63% was achieved within the first 90 min of performing the test under UV light. The photocatalytic printed film was addressed the issue of filtering the unused suspension of nanoparticles, which made it difficult to remove the particles from the treated wastewater, in terms of sustainability. The fabricated patterns using Paste B exhibited improved properties, including electrical conductivity, antibacterial and photocatalytic activity.

Preparation of Electrochemical Supercapacitor Based on Polypyrrole/Gum Arabic Composites

The current research focused on the super capacitive behavior of organic conducting polymer, i.e., polypyrrole (PPy) and its composites with gum arabic (GA) prepared via inverse emulsion polymerization. The synthesized composites material was analyzed by different analytical techniques, such as UV-visible, FTIR, TGA, XRD, and SEM. The UV-Vis and FTIR spectroscopy clearly show the successful insertion of GA into PPy matrix. The TGA analysis shows high thermal stability for composites than pure PPy. The XRD and SEM analysis show the crystalline and amorphous structures and overall morphology of the composites is more compact and mesoporous as compared to the pure PPy. The electrochemical properties of modified solid state supercapacitors established on pure polypyrrole (PPy), polypyrrole/gum arabic (PPy/GA) based composites were investigated through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge (GCD). The specific capacitance of the PPy modified gold electrode is impressive (~168 F/g). The specific capacitance of PPy/GA 1 electrode has been increased to 368 F/g with a high energy density and power density (~73 Wh/kg), and (~599 W/kg) respectively.