Fabrication and characterization of dry conducting polymer actuator by vapor phase polymerization of polypyrrole.

A trilayered dry conducting polymer actuator was fabricated via application of a polypyrrole (PPy) coating on both sides of a solid polymer electrolyte film using vapor phase polymerization (VPP). The solid polymer electrolyte film was prepared by incorporation of different weight ratios of dodecylbenzene sulfonic acid sodium salt in poly(vinyl alcohol) (PVA) by solvent casting. The successful polymerization of PPy was confirmed by Fourier transform infrared spectroscopy; a uniform PPy coating on the solid polymer electrolyte film surface was also observed by scanning electron microscopy. The dry PVA/PPy actuator demonstrated good actuation behavior at a low applied voltage of 1-3 V. The actuator bending displacement was found to increase with an increase in the applied voltage. The VPP approach in this study provides a very effective method for achieving a uniform polymer coating in the fabrication of a dry conducting polymer actuator.

Piezoelectric Biosensors and Nanomaterials-based Therapeutics for Coronavirus and Other Viruses: A Mini-review.

Since late 2019, the novel coronavirus (COVID-19) pandemic has caused considerable mortality worldwide. This pandemic raised concerns and provoked research on the diagnosis and treatment of viruses-based diseases. The accurate diagnosis of a virus requires high specificity and sensitivity. Piezoelectric sensors are analytical devices that work on mass-sensitivity-based micromechanical transducers. The change in the mass by the interaction between biological elements and the frequency is recorded by measuring the alternate current and voltage. In addition to diagnosis, antiviral intervention strategies for mitigating various viral diseases are required. Nanomaterialsbased antiviral therapy is efficient, particularly with carbon/metal/metal oxide (organic/inorganic) nanoparticles. Metal/metal oxide nanoparticles, such as gold (Au), silver (Ag), copper (Cu), selenium (Se), zinc oxide (ZnO), magnesium oxide (MgO), carbon dots (CDs), and carbon quantum dots (CQDs), are promising candidates for antiviral therapy. This review discusses the piezoelectric sensors used to detect various viruses, including COVID-19, and the various organic and inorganic nanoparticles involved in the antiviral therapy.

Solution-Processed PEDOT:PSS/MoS2 Nanocomposites as Efficient Hole-Transporting Layers for Organic Solar Cells.

An efficient hole-transporting layer (HTL) based on functionalized two-dimensional (2D) MoS2-poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) composites has been developed for use in organic solar cells (OSCs). Few-layer, oleylamine-functionalized MoS2 (FMoS2) nanosheets were prepared via a simple and cost-effective solution-phase exfoliation method; then, they were blended into PEDOT:PSS, a conducting conjugated polymer, and the resulting hybrid film (PEDOT:PSS/FMoS2) was tested as an HTL for poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) OSCs. The devices using this hybrid film HTL showed power conversion efficiencies up to 3.74%, which is 15.08% higher than that of the reference ones having PEDOT:PSS as HTL. Atomic force microscopy and contact angle measurements confirmed the compatibility of the PEDOT:PSS/FMoS2 surface for active layer deposition on it. The electrical impedance spectroscopy analysis revealed that their use minimized the charge-transfer resistance of the OSCs, consequently improving their performance compared with the reference cells. Thus, the proposed fabrication of such HTLs incorporating 2D nanomaterials could be further expanded as a universal protocol for various high-performance optoelectronic devices.

Functionalization of graphene with self-doped conducting polypyrrole by click coupling.

The synthesis of self-doped conducting polypyrrole-grafted graphene sheets (GS-PPy) for non-volatile memory applications is reported. First, the alkyne-modified graphene sheets (GS-alkyne) were covalently functionalized with a water-soluble polymer containing numerous anionic SO3(-) dopants by a copper-catalyzed click reaction. Then, polypyrrole was covalently grafted onto the functionalized graphene sheets by chemical oxidative polymerization to produce GS-PPy hybrids. The GS-PPy hybrids showed a uniform coating of PPy on the GS sheets, good dispersion in aqueous solutions, high electrical conductivity, and red-shifted absorption peak in the UV/Visible spectra. The non-volatile memory device composed of a Al/(GS-PPy/poly(vinyl alcohol))/Al structure, produced by spin coating of the aqueous GS-PPy/poly(vinyl alcohol) solution, showed a good write-once read-many times memory behavior, which was due to good electrical and optical absorption properties of the GS-PPy hybrids. The findings of this study provide a potential solution for the fabrication of water-soluble graphene-based hybrids for non-volatile resistive-memory-based applications.