PEO|Sncl2|PANI composites: as an electrolyte in solid-state battery

Solid-state polymer electrolytes possess high conductivity and have advantages compared with their liquid counterparts. The polyethylene oxide (PEO)-based polymer is a good candidate for this purpose. The PEO/SnCl₂/polyaniline composite (PSP composites) at different weight percentages were prepared in anhydrous acetonitrile media. Structural studies were carried out of the prepared composites by X-ray diffraction, Fourier transmission infrared spectroscopy, and surface morphology by scanning electron microscopy. The σ _dc was carried out by a two-probe method, and it is found that the conductivity increases with an increase in temperature. The temperature-dependent conductivity of the composites exhibits a typical semi-conducting behavior and hence can be explained by the 1D variable range hopping model proposed by Mott. The electrochemical cell parameters for battery applications at room temperature have also been determined. The samples are fabricated for battery application in the configuration of Na: (PSP): (I₂?+?C?+?sample), and their experimental data are measured using Wagner’s polarization technique. The cell parameters result in an open-circuit voltage of 0.83 V and a short-circuit current of 912 μA for PSP (70:30:10) composite. Hence, these composites can be used in polymer electrolyte studies.     

A Comprehensive Outlook of Synthetic Strategies and Applications of Redox‐Responsive Nanogels in Drug Delivery

Increasing recognition of the role of oxidative stress in the pathogenesis of many clinical conditions and the existence of defined redox potential in healthy tissues has led to extensive research in the development of redox‐responsive materials for biomedical applications. Especially, considerable growth has been seen in the fabrication of polymeric nanogel–based drug delivery carriers utilizing redox‐responsive cross‐linkers bearing a variety of functional groups via various synthetic strategies. Redox‐responsive polymeric nanogels provide an advantage of facile chemical modification post synthesis and exhibit a remarkable response to biological redox stimuli. Due to the interdisciplinary nature of the subject, a more profound combined conceptual knowledge from a chemical and biological point of view is imperative for the rational design of redox‐responsive nanogels. The present review provides an insight into the design and fabrication of redox‐responsive nanogels with particular emphasis on synthetic strategies utilized for the development of redox‐responsive cross‐linkers, polymerization techniques being followed for nanogel development and biomedical applications. Cooperative effect of redox trigger with other stimuli such as pH and temperature in the evolution of dual and triple stimuli‐responsive nanogels is also discussed.     

Poly (3,4‐ethylenedioxythiophene) γ‐Fe2O3 polymer composite–super paramagnetic behavior and variable range hopping 1D conduction mechanism–synthesis and characterization

The present paper reports the preparation of poly (3,4‐ethylenedioxythiophene) (PEDOT) ferrimagnetic conducting polymer composite by incorporation of ferrite particles in the polymer matrix by emulsion polymerization. Synthesis of PEDOT–γ‐Fe₂O₃ composite was carried out by chemical oxidative polymerization of EDOT with ferrite particles in the presence of dodecylbenzenesulfonic acid (DBSA) that works as dopant as well as surfactant in aqueous medium. The resulting conducting composite possesses saturation magnetization (Ms) value of 20.56 emu/g with a conductivity of 0.4 Scm^?1, which was determined by VSM and four probe technique, respectively. B‐H curve reveals that ferrimagnetic particles of γ‐Fe₂O₃ show super‐paramagnetic behavior at room temperature which was also observed in PEDOT–γ‐Fe₂O₃ composite. The resulting conducting ferrimagnetic composite shows microwave absorption loss of 18.7–22.8 dB in the frequency range of 12.4–18 GHz. Thermogravimetric analysis of the composite revealed that the composite is thermally stable up to 230°C. The characterization of the PEDOT–γ‐Fe₂O₃ composite was carried out using XRD and FTIR spectroscopy. Copyright © 2007 John Wiley & Sons, Ltd.     

Electrical properties and EMI shielding behavior of highly thermally stable polyaniline/colloidal graphite composites

A hybrid approach has been adopted by using a combination of colloidal graphite (CG) as a conducting filler, 5‐lithium sulfoisophthalic (LiSIPA) acid as a dopant, and polyaniline (PANI) as a matrix to prepare LiSIPA doped PANI–CG composites. The thermal stability (～300°C) and electrical conductivity (67.4 S/cm at 17.4% CG content) have been improved significantly as compared to PANI doped with conventional inorganic dopants like HCl or H₂SO₄ (130–150°C). The maximum shielding effectiveness value was found to be ?39.7 dB. X‐ray diffraction and infrared spectroscopy showed a systematic shifting of the characteristic peaks and bands with increase in the amount of CG, which indicates significant interaction exists between CG and PANI. The UV–Vis spectra showed the characteristic bands of PANI, with a shift to shorter wavelength with increase in the CG content. The interaction mechanism between doped PANI and CG in the resultant composites has been proposed. Copyright © 2009 John Wiley & Sons, Ltd.     

New Insight into Biodegradation of Polylactide (PLA)/Clay Nanocomposites Using Molecular Ecological Techniques

Novel molecular ecological techniques were used to study changes in microbial community structure and population during degradation of polylactide (PLA)/organically modified layered silicates (OMLS) nanocomposites. Cloned gene sequences belonging to members of the phyla Actinobacteria and Ascomycota comprized the most dominant groups of microorganisms during biodegradation of PLA/OMLS nanocomposites. Due to their numerical abundance, members of these microbial groups are likely to play an important role during biodegradation process. This paper presents new insights into the biodegradability of PLA/OMLS nanocomposites and highlights the importance of using novel molecular ecological techniques for in situ identification of new microorganisms involved in biodegradation of polymeric materials.

     

Ultrasonic velocity, density, viscosity and their excess parameters of the binary mixtures of tetrahydrofuran with methanol and o-cresol at varying temperatures

The ultrasonic velocity, density and viscosity of binary mixtures of tetrahydrofuran (THF) with methanol and o-cresol were measured at 293, 303 and 313 K over the entire range of composition. Using these experimental data, various thermo-acoustic parameters such as deviation in isentropic compressibility Δκ_s, excess molar volume , viscosity deviation Δη and excess Gibb’s free energy of activation for viscous flow ΔG^∗E have been calculated and fitted to Redlich-Kister polynomial equation. The deviation/excess parameter were plotted against the mole fraction of THF over the whole composition range. The observed negative and positive values of deviation/excess thermo-acoustic parameters were explained on the basis of the intermolecular interactions present in these mixtures. Since methanol is less acidic than o-cresol, the removal of proton from methanol is less likely than the removal of proton from o-cresol which is more acidic than methanol. Hence the intermolecular interaction in the mixture of THF with o-cresol is found to be stronger than mixture of THF with methanol, which is reflected from the observed positive and negative values of excess thermo-acoustic parameters. Thus it may be concluded that THF + o-cresol mixture exhibits strong intermolecular interaction. However, dispersive forces are responsible for THF + methanol mixture due to weak interaction. Further, Nomoto, Junjie, CFT and Flory’s theory were applied for evaluating the ultrasonic velocity theoretically. The theoretical evaluation of ultrasonic velocity based on molecular models in liquid mixtures has been used to correlate with the experimental findings and to know the thermodynamics of the mixtures. The comparison of theoretical and experimental results provides better understanding about the validity of the various thermodynamic, empirical, semi empirical and statistical theories.     

Projective synchronization of time‒delayed chaotic systems with unknown parameters using adaptive control method

The present article aims to study the projective synchronization between two identical and non?identical time?delayed chaotic systems with fully unknown parameters. Here the asymptotical and global synchronization are achieved by means of adaptive control approach based on Lyapunov–Krasovskii functional theory. The proposed technique is successfully applied to investigate the projective synchronization for the pairs of time?delayed chaotic systems amongst advanced Lorenz system as drive system with multiple delay Rössler system and time?delayed Chua's oscillator as response system. An adaptive controller and parameter update laws for unknown parameters are designed so that the drive system is controlled to be the response system. Numerical simulation results, depicted graphically, are carried out using Runge–Kutta Method for delay?differential equations, showing that the design of controller and the adaptive parameter laws are very effective and reliable and can be applied for synchronization of time?delayed chaotic systems. Copyright © 2014 John Wiley & Sons, Ltd.