Polypyrrole Polyethylene Composite for Controllable Linear Actuators in Different Organic Electrolytes

Controllable linear actuation of polypyrrole (PPy) is the envisaged goal where only one ion dominates direction (here anions) in reversible redox cycles. PPy with polyethylene oxide (PEO) doped with dodecylbenzenesulfonate forms PPy-PEO/DBS films (PPy-PEO), which are applied in propylene carbonate (PC) solvent with electrolytes such as 1-ethyl-2,3-dimethylimidazolium trifluoromethanesulfonate (EDMICF3SO3), sodium perchlorate (NaClO4) and tetrabutylammonium hexafluorophosphate (TBAPF6) and compared in their linear actuation properties with pristine PPy/DBS samples. PPy-PEO showed for all applied electrolytes that only expansion at oxidation appeared in cyclic voltammetric studies, while pristine PPy/DBS had mixed-ion actuation in all electrolytes. The electrolyte TBAPF6-PC revealed for PPy-PEO best results with 18% strain (PPy/DBS had 8.5% strain), 2 times better strain rates, 1.8 times higher electronic conductivity, 1.4 times higher charge densities and 1.5 times higher diffusion coefficients in comparison to PPy/DBS. Long-term measurements up to 1000 cycles at 0.1 Hz revealed strain over 4% for PPy-PEO linear actuators, showing that combination of PPy/DBS with PEO gives excellent material for artificial muscle-like applications envisaged for smart textiles and soft robotics. FTIR and Raman spectroscopy confirmed PEO content in PPy. Electrochemical impedance spectroscopy (EIS) of PPy samples revealed 1.3 times higher ion conductivity of PPy-PEO films in PC solvent. Scanning electron microscopy (SEM) was used to investigate morphologies of PPy samples, and EDX spectroscopy was conducted to determine ion contents of oxidized/reduced films.

Molecular Structure, Hirshfeld Surface Analysis, Optical and Electrochemical Studies of Stable Solid Diazonium Salt of p-Sulphophenyl-3-methyl-5-pyrazolone

The title compound is a new pyrazolone derivative which was synthesized starting from p-sulphophenyl-3-methyl-5-pyrazolone (1) by nitrosation at low temperature to afford the corresponding p-sulphophenyl-3-methyl-4-nitroso-5-pyrazolone which can exist both in nitroso (2a) and oxime tautomeric forms (2b). Reduction of the latter using zinc with hydrochloric acid furnished the 4-amino-p-sulphophenyl-3-methyl-5-pyrazolone (3). The diazotization of (3) under careful control of temperature and pH afforded the p-Sulphophenyl − 3-methyl-5-pyrazolone diazonium salt (4) which was re-crystallized from acidified ethanol to afford crystal suitable for X-ray studies. UV-visible spectrum and cyclic voltammetric studies were also carried out indicating λmax at 420 nm and HOMO-LUMMO energy gap was also calculated (Eg) of 2.95 eV. The molecular and crystal structures of the compound were clarified by single crystal X-ray diffraction indicated that it crystallizes as the sodium salt in the triclinic space group P -1, with the 4-azo-pyrazolone and the sulphophenyl groups being nearly coplanar. To get an insight to the intermolecular interactions in the crystal a Hirshfeld surface analysis was also carried out.

Spectroelectrochemical Properties and Catalytic Activity in Cyclohexane Oxidation of the Hybrid Zr/Hf-Phthalocyaninate-Capped Nickel(II) and Iron(II) tris-Pyridineoximates and Their Precursors

The in situ spectroelectrochemical cyclic voltammetric studies of the antimony-monocapped nickel(II) and iron(II) tris-pyridineoximates with a labile triethylantimony cross-linking group and Zr(IV)/Hf(IV) phthalocyaninate complexes were performed in order to understand the nature of the redox events in the molecules of heterodinuclear zirconium(IV) and hafnium(IV) phthalocyaninate-capped derivatives. Electronic structures of their 1e-oxidized and 1e-electron-reduced forms were experimentally studied by electron paramagnetic resonance (EPR) spectroscopy and UV−vis−near-IR spectroelectrochemical experiments and supported by density functional theory (DFT) calculations. The investigated hybrid molecular systems that combine a transition metal (pseudo)clathrochelate and a Zr/Hf-phthalocyaninate moiety exhibit quite rich redox activity both in the cathodic and in the anodic region. These binuclear compounds and their precursors were tested as potential catalysts in oxidation reactions of cyclohexane and the results are discussed.

Electrochemical behavior of various implantation biomaterials in the presence of various simulated body fluids: An overview

In Modern medicine, metals and alloys are being used as implants. The Corrosion behaviour of various biomaterials under artificial body fluids are being studied. Artificial biomaterials are being implanted inside the human body to replace bone, teeth, etc. Even organs are being medically substituted with different types of metals such as mild steel, carbon steel, Ni-Cr alloy, Fe-Cr alloy, 22 carat Gold,24 carat Gold Tin, etc. due to their biocompatibility. This is achieved by connecting these metals directly with body tissues. The metals tend to corrode when it gets in contact with human body fluids. The body fluids thereby come in direct contact with tissues and the tissues are in contact with the metal thus causing the metal to corrode. And hence the corrosion resistance studies such as polarisation, AC impedance, cyclic voltammetric studies, etc, are being conducted in a medium like artificial blood plasma, artificial urine, artificial salvia, artificial sweat, Hank solution, Ringer solution, etc. The different body fluids are examined in the presence of different implantation metals by electrochemical methods and protective films are formed which are analyzed by various surface analysis techniques such as AFM, FTIR-UV, SEM, etc. The research findings will thereby be very helpful to the medical field.

Electrodeposition of Zn-Fe Alloy from Non-Cyanide Alkaline Sulphate Bath Containing Tartarate

Electrodeposition of Zn-Fe alloy from an alkaline sulphate bath containing tartarate has been carried out. The effect of plating variables on the composition of alloy and on cathodic current efficiency was studied. The cyclic voltammetric studies carried out to know the mutual co-deposition of zinc and iron. Hardness and the surface morphology of the alloy deposits were found to be dependent on the iron content in the alloy. An alloy containing 20% wt. Fe showed smooth, uniform and finer grained deposits. Under the optimum composition and operating conditions, Zn-Fe alloy deposition from alkaline sulphate bath containing tartarate followed anomalous depositing process.

Phyto-Assisted Synthesis and Characterization of V2O5 Nanomaterial and their Electrochemical and Antimicrobial Investigations

The chemical and physical synthetic strategies for the preparation of nanomaterials are time-consuming, costly and toxic. To address these issues, Phyto-assisted synthesis of nanomaterials can be considered as a promising strategy. Herein, V2O5 nanomaterial has been synthesized by using Azadirachta indica (Neem) leaf extract. The V2O5 nanomaterial was characterized by employing multiple techniques, such as UV-Vis, FTIR, XRD, FE-SEM and EDX. The results showed that V2O5 nanomaterial possesses nanoplate’s type morphology with 30–50[Formula: see text]nm diameters. Further, cyclic voltammetric studies showed the good durability during the voltammetric scans in 2M KCl electrolyte at 50[Formula: see text]mV/s scan rate and the V2O5 nanoplates may be served as a promising cathodic candidate in Li-ion secondary batteries. Moreover, the antimicrobial activity of the prepared V2O5 nanoplates was evaluated against the bacteria viz. S. typhi, S. aureus, B. subtilis, E. coli and fungi; F. species, A. flavus, P. triticina and A. niger by using the serial dilution method. The results suggested that V2O5 nanoplates possess comparable antimicrobial activity comparable to standard drug Streptomycin against the used pathogens.