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.

A Kinetic Study of 2-Amino-4-(Methyl-Thio) Butanoic Acid By Quinaldinium Fluorochromate In Selected Hydrophilic Solvent Medium

A Major role in oxidation kinetics is to determine the reaction mechanism that comprise chemical reaction. In the present paper we derived rate law for reaction mechanism and to recognized the order of reaction, give rate equation, calculate the rate constant. Identify the product of this oxidation reaction.The chemical oxidation of 2-Amino-4-methyl thio-butanoic acid by Quinaldinium Fluorochromate was studied in 50-50 (v/v) selected hydrophilic solvent medium at 308 Kelvin. The reaction is acid catalysed and exhibits first order dependence with respect to oxidant, substrate, and fractional order respect to H+ ion concentrations. Chemical oxidation kinetics is the study of the rate of chemical reaction.the factors Manganesh sulphate, Acrylonitrile, Sodium perchlorate that affect these rates (or) not, and draw of ln Kobs/T verses 1/T energy diagram to find the activation energy. Addition of sodium perchlorate slightly decreases the rate of reaction. However, Acrylonitrile is not induced by the polymerization reaction, showing that there is no free radical route. Added Mn2+ increases with slightly increase rate in the reaction medium. 2-Amino-4-(MethylThio)-Butanoic acid by Quinaldinium Fluorochromate has not been reported. Hence, the investigation of oxidation of 2-Amino-4-Methyl Thio-Butanoic acid by QNFC in selected hydrophilic solvent medium and the corresponding mechanistic aspects are discussed in this research paper. A systematic kinetic work carried out to explore the physical characterization of the reactance. The characterstic effects like Substrate, Oxidant, Perchloric acid, Solvent, Sodium perchlorate, Acrylonitrile, Manganes sulphate and Influence Temperature it clearly shows effect on that reaction path. The process was carried out at four different temperatures to determine the activation conditions. The measured kinetic findings ΔH# and ΔS# are derived from the value.

RP-HPLC QUANTIFIABLE TECHNIQUE DEVELOPMENT FOR EVALUATING PREGABALIN AND ETORICOXIB COMBINATION IN TABLET AND BULK KINDS

Objective: This evaluation study aims to initiate a relatively sensitive RP-HPLC quantifiable technique for evaluating pregabalin (PRBN) and etoricoxib (ETRB) combination in tablet and bulk kinds. Methods: PRBN and ETRB chromatographic evaluations were carried off using the “KNAUER C18 Eurospher II column (250 mm × 4.6 mm × 5 μ)”. The mobile phase (MBP) was driven into the KNAUER C18 Eurospher II column at a 1.0 ml/min run rate with an isocratic elution programme of 65% volume of 0.5 mmol sodium perchlorate 35% volume methanol, detected and evaluated the PRBN and ETRB content at 217 nm. Results: The analysis of PRBN and ETRB is executed inside a run period of 15 min. The RP-HPLC quantifiable technique was developed to separate PRBN and ETRB and likely degradants formed from stress testing by isocratic elution. The RP-HPLC quantifiable technique developed was successfully validated to existing ICH limit guidelines and was confirmed as robust, specific, accurate, selective, precise, sensitive, and linear. Conclusion: The RP-HPLC quantifiable technique developed here is more valuable and worthy for routine PRBN and ETRB analysis of tablets and bulk kinds.

Polypyrrole with Phosphor Tungsten Acid and Carbide-Derived Carbon: Change of Solvent in Electropolymerization and Linear Actuation

Linear actuators based on polypyrrole (PPy) are envisaged to have only one ion that triggers the actuation direction, either at oxidation (anion-driven) or at reduction (cation-driven). PPy doped with dodecylbenzenesulfonate (PPy/DBS) is the most common applied conducting polymer having cation-driven actuation in aqueous solvent and mainly anion-driven actuation in an organic electrolyte. It is somehow desired to have an actuator that is independent of the applied solvent in the same actuation direction. In this research we made PPy/DBS with the addition of phosphorus tungsten acid, forming PPyPT films, as well with included carbide derived carbon (CDC) resulting in PPyCDC films. The solvent in electropolymerization was changed from an aqueous ethylene glycol mixture to pure EG forming PPyPT-EG and PPyCDC-EG composites. Our goal in this study was to investigate the linear actuation properties of PPy composites applying sodium perchlorate in aqueous (NaClO4-aq) and propylene carbonate (NaClO4-PC) electrolytes. Cyclic voltammetry and square potential steps in combination with electro-chemo-mechanical-deformation (ECMD) measurements of PPy composite films were performed. The PPyPT and PPyCDC had mixed ion-actuation in NaClO4-PC while in NaClO4-aq expansion at reduction (cation-driven) was observed. Those novel PPy composites electropolymerized in EG solvent showed independently which solvent applied mainly expansion at reduction (cation-driven actuator). Chronopotentiometric measurements were performed on all composites, revealing excellent specific capacitance up to 190 F g−1 for PPyCDC-EG (best capacitance retention of 90% after 1000 cycles) and 130 F g−1 for PPyPT-EG in aqueous electrolyte. The films were characterized by scanning electron microscopy (SEM), Raman, Fourier-transform infrared (FTIR) and energy dispersive X-ray spectroscopy (EDX).

Voltammetric Determination of Isopropylmethylphenols in Herbal Spices

Thymol and carvacrol—the components of herbal spices—are known for their broad biological activity as antimicrobials and antioxidants. For this reason, it is important to develop new methods for their determination in plant material. A simple, rapid, and sensitive method for determination of total content of these analytes in herbal spices using differential pulse voltammetry (DPV) has been developed. The basis of the research is the oxidation process of isopropylmethylphenols on a platinum microelectrode in glacial acetic acid containing acetonitrile (20%, v/v) and 0.1 mol L−1 sodium perchlorate as the supporting electrolyte. Linear voltammetric responses for thymol and carvacrol were obtained in a wide concentration range from 0.39–1105 and 0.47–640 µg mL−1, with a low detection limit of 0.04 and 0.05 µg mL−1, respectively. The analysis was performed using the multiple standard addition method. The results of the voltammetric determination are in good agreement with the data of the standard chromatographic method. To the best of our knowledge, this is the first presentation of an electrochemical procedure to determine these compounds in these environmental and electrode materials.

Effect of new crystalline phase on the ionic conduction properties of sodium perchlorate salt doped carboxymethyl cellulose biopolymer electrolyte films

Dopant induced modifications in the microstructure of sodium carboxymethyl cellulose (NaCMC) were characterized by FTIR, XRD, DSC and EIS techniques. FTIR analysis exhibited a considerable microstructural modification in NaCMC upon NaClO4⋅H2O doping invoked through complex formation via Lewis acid-base interaction and hydrogen bond formation between ions and dipoles. This resulted in the modification in the orderliness/disorderliness of polymer chains as observed from XRD deconvolution. At higher salt concentrations, the complexity of the network causes the formation of new amorphous and crystalline phases as reflected in the XRD studies. DSC analysis showed an increase in Tg as the salt concentration increased, indicating a reduction in polymer chains flexibility. The contribution of free ions has masked over the enhancement in amorphous content to conductivity at a lower concentration of salt in the matrix, later on, the formation of a new crystalline phase due to transient crosslinks by Na+…ClO4−…Na+ has affected the ion transport process.

Stability Indicating RP-HPLC Method for the Analysis of Dacomitinib and its Related Impurities in Bulk and Oral Solid Dosage Formulations

Dacomitinib is an epidermal growth factor receptor inhibitor prescribed for the treatment of metastatic non small-cell lung carcinoma. There are no reported significant official of HPLC methods that resolve the impurities and degradation products generated during stability studies. Therefore, an isocratic RP-HPLC-UV method was developed for the determination of Dacomitinib in the presence of its related impurities and degradation products. The separation of Dacomitinib, impurity 1 and 2 was achieved on Agilent ZORBAX Eclipse (250×4.6 mm; 5 µ id) column as stationary phase, 0.1M sodium perchlorate at pH 5.6, acetonitrile as mobile phase in the ratio of 20:80 (V/V) at a flow rate of 1.0 mL/min in isocratic condition as mobile phase and UV detection was carried at 253 nm. In the optimised conditions, well resolved and retained peaks were observed at a retention time of 5.8 min, 4.0 min and 7.7 min for Dacomitinib, impurity 1 and 2 respectively. In the developed method, a very sensitive detection limit of 0.06 and 0.025 µg/mL was observed for impunity 1 and 2 respectively. The calibration was observed to be within the concentration range of 20 – 200 µg/mL for Dacomitinib and 0.2 – 2 µg/mL for impurity 1 and 2. The proposed method was used to investigate the effective separation of impurities along with degradation compounds formed under different degradative conditions and confirms that the method is stability indicating. Hence it can be concluded that the method was found to be simple, sensitive, specific, accurate, linear, precise, rugged, robust, and useful for estimation and characterizing the stability of Dacomitinib, impurity 1 and 2.

Redetermination of the crystal structure of bis[N,N′-ethylenebis(acetylacetoniminato)nickel(II)] sodium perchlorate, C24H36ClN4NaNi2O8

C24H36ClN4NaNi2O8, monoclinic, C2/c (no. 15), a = 19.5909(11) Å, b = 10.8023(6) Å, c = 14.5722(8) Å, β = 112.032(1)°, V = 2858.7(3) Å3, Z = 4, R gt (F) = 0.0260, wR ref (F 2) = 0.0701, T = 93(2) K.