Poonam Bandyopadhyay

Significant enhancement of dielectric and conducting properties of electroactive polymer polyvinylidene fluoride films: An innovative use of Ferrum metallicum at different concentrations

Background: There are experimental evidences of nanoparticle aspect of homoeopathic medicine. It has also been established that the size of these nanoparticles (NPs) decrease with increase in potency. Aim: We have used this aspect of homoeopathic medicines in some technical applications. Here, to improve the electrical properties of an electroactive polymer, poly (vinylidene fluoride-hexa-fluoropropylene) (PVDF-HFP), we have incorporated in the polymer film, a very novel and unique probe Ferrum metallicum (FeM), a homoeopathic medicine, the size of which can be changed by dilution, followed by controlled agitation. Settings and Design: The composite film was synthesized by solution-casting technique. Using standard procedures, the characterization studies by X-ray diffraction, field-emission scanning electron microscope, and Fourier transform infrared spectroscopy were performed to check the incorporation of the NPs in the film. Material and Method: Each sample was freshly prepared 2 times by doping FeM in PVDF-HFP matrix using solution-casting technique, and the experiment was repeated with each sample for 5 times. Statistical Analysis: This being a continuous data recording, error bars cannot be shown. We have presented the graphs which have been repeated maximum number of times. Result and Conclusion: Our result shows that the electrical properties such as dielectric constant, tangent loss, and electrical conductivity of these polymer films get significantly modified due to incorporation of this homoeopathic nanomedicine and the effect increases with the increase in concentration of the probe up to a critical value. These FeM-incorporated PVDF-HFP films will have potential applications as high-energy storage devices such as multilayered high-charge storage device.

Enhanced dielectric properties and conductivity of triturated copper and cobalt nanoparticles-doped PVDF-HFP film and their possible use in electronic industry

We have synthesised a novel nanocomposite film by incorporating copper and cobalt nanoparticles, prepared by the method of trituration, in the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) films by simple solution-casting technique. Fourier transform infrared spectroscopy (FTIR) study of these nanocomposite films detected presence of α- and β-phases. Scanning electron micrographs showed spherulitic crystal structure of PVDF-HFP in the nanocomposite film and study of dielectric properties over broadband frequency of these doped nanocomposite film showed that these films have higher dielectric permittivity and significantly lower dissipation factor (tanδ) at room temperature compared to the pure PVDF-HFP. The incorporation of metallic nanoparticles in the polymer matrix activates the transition of phase between α and β and provides the nanocomposites higher mobile charge carriers which participate in the interfacial polarisation. The room temperature dielectric constant of the pure PVDF-HFP at 20 Hz frequency increases with increase in concentration of the metal nanoparticles and reaches a maximum almost four times the value of the pure one. At higher concentrations, the effect reduces, perhaps due to agglomeration of the nanoparticles. The metal nanoparticles, obtained by the method of trituration, are inexpensive, easy to fabricate and environment friendly. Thus, their incorporation in polymer matrix to get enhanced electrical properties will have a significant contribution to the present day research.

Effect of Cu doping in ZnO nanoparticles for increased voltage generation, storage capacity, and energy conversion efficiency in photoelectrochemical cell

ABSTRACT The synthesis, characterization, and application of engineered nanomaterials in different fields have opened up new aspects of nanotechnology. Using a simple chemical method, this study describes the synthesis of highly dispersed Cu-doped ZnO nanoparticles with different concentrations of Cu (1, 3, and 5 mM). The nanoparticles thus synthesized were tested for their effect on photo-induced voltage generation, enhancement of storage capacity, and energy conversion efficiency in hybrid photoelectrochemical (PEC) cell. Maximum photovoltage (~680 mV) with highest storage capacity (~53 h) and high energy conversion efficiency (~2.16%) was generated using these nanoparticles when the doping concentration of Cu was 3 mM.

Efficiency of a dye-sensitized photoelectrochemical device using thionine and triturated zinc oxide at different potency

ABSTRACT A new and novel material, triturated zinc oxide nanoparticles, which is eco-friendly, easily available, low in cost, has been used here for the first time for enhancement of photovoltage generation and efficiency of a dye-sensitized photoelectrochemical device. This material when diluted and strongly agitated, together termed as potentized, is used as nanomedicine for centuries. This study using this material at two different potencies (6C and 30C) shows that addition of this material to thionine dye of concentration 0.85 μM enhances photovoltage generation significantly. The efficiency obtained with the latter is ~0.41%, whereas it is ~0.003% with dye only.

Effect of Homeopathic Dilutions of Cuprum Arsenicosum on the Electrical Properties of Poly(Vinylidene Fluoride-Co-Hexafluoropropylene)

BACKGROUND We report the effects of nanoparticles in homeopathic preparations of copper salts on the electrical properties of polymer film. Previous work showed that the incorporation of metal-derived homeopathic medicines increases the dielectric constant and alternating current (AC) conductivity of an electroactive polymer film that is commonly used as a capacitor in the electronic industry.We report here the effect of dilution of one homeopathic medicine, Cuprum arsenicosum (CuAs), at 200C potency on the electrical properties of the polymer film of poly(vinylidene fluoride-co-hexafluoropropylene). METHODS CuAs 200c was incorporated in the film by the solution casting method. The electrical characteristics were measured at different frequencies using an inductance, capacitance, and resistance meter. Fourier transform infrared spectroscopy (FTIR) was performed to detect phase change in the polymer film due to the incorporation of CuAs. Morphology and particle size were studied using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy. RESULTS At 10 kHz frequency, both dielectric constant and AC conductivity increased approximately 18 times for the polymer film when incorporated with 2 mL CuAs at 200C potency. FTIR indicated the increase in conducting phase, while FESEM and EDX confirmed the presence of spherical CuAs particles. CONCLUSION The incorporation of CuAs in the electroactive polymer film enhances the conductivity and dielectric constant. We conclude that these changes arise from the change in phase of the polymer film, and because of the presence of two different metals that affects the interfacial polarization.