Increase of Solid Polymer Electrolyte Ionic Conductivity Using Nano-SiO2 Synthesized from Sugarcane Bagasse as Filler

The synthesize of solid polymer electrolyte (SPE) based on polyethylene oxide (PEO), NaClO4 and nano-SiO2 was carried out by solution cast technique. Nano-SiO2 was synthesized from sugarcane bagasse using sol-gel method. FTIR analysis was carried out to investigate the bonding between nano-SiO2 and PEO/NaClO4. The morphology of the SPE was characterized using SEM. XRD and DSC analysis showed that SPE crystallinity decreased as nano-SiO2 concentration was increased. Mechanical analyses were conducted to characterize the SPE tensile strength and elongation at break. EIS analysis was conducted to measure SPE ionic conductivity. The PEO/NaClO4 SPE with the addition of 5% nano-SiO2 from sugarcane bagasse at 60 °C produced SPE with the highest ionic conductivity, 1.18 × 10−6 S/cm. It was concluded that the addition of nano-SiO2 increased ionic conductivity and interface stability at the solid polymer electrolyte-PEO/NaClO4.

Investigate the Thermal Analysis Properties of Polymer Electrolyte

Propylene carbonate (PC) (1:1) have been used as plasticizer to synthesized two series of polymer blend electrolytes (As and Cs) composed of Poly (methyl methacrylate) (PMMA)/Polyacrylonitrile (PAN), (80/20) Wt.% and ethylene carbonate (EC) using solution cast technique. Mixed iodide salts and varying weight ratio of potassium iodide (KI) and cesium iodide (CsI) was used to study the thermal properties of polymer blend electrolytes (GPEs). Differential Scanning Calorimeter (DSC) results show a decrease in the glass transition of electrolytes when increasing the weight percentage of salts, while the melting point increases due to the reduction in the polymer fluidity. Thermogravimetric analysis (TGA) indicates that the increase in the thermal stability can be attributed to the high thermal stability of polymer blend and the existence of the strong interaction between the two polymers. The optimum value of glass transition (Ts) is 104.2 °C found in sample containing 35 Wt.% of KI salt which has a melting point (Tm) 194.7 °C.

CuO and MWCNTs Nanoparticles Filled PVA-PVP Nanocomposites: Morphological, Optical, Thermal, Dielectric, and Electrical Characteristics

Copper dioxide (CuO) nanoparticles and Multiwall carbon nanotubes (MWCNTs) filled poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) blend matrix (50/50 wt%) based polymer nanocomposites (PNCs) (i.e., PVA/PVP:(15-x)CuO(x)MWCNTs for x=0,1,5,7.5, 10,14, and 15wt%) have been prepared employing the solution-cast method. The morphologies of these PNCs are semicrystalline, according to an X-ray diffraction investigation. The FTIR, SEM, and AFM measurements of PNCs were used to investigate the development of the miscible mix, polymer-polymer and polymer–nanoparticle interactions, and the influence of CuO and MWCNTs nanofillers on the morphology aspects on the main chain of PVA/PVP blend. The nanofiller dispersion signposting for x=14 wt% nanoloading in the PVA–PVP blend matrix significantly enhances the crystalline phase, diminishing the optical energy gap to 2.31eV. The DC conductivity values augment with the upsurge in nanofiller level for maximum x=14wt%. The dielectric and electrical characteristics of these PNCs are investigated for an applied frequency range from 1kHz to 1 MHz. The enhancement in the nanofiller level upto x=14wt% in the PVA/PVP matrix leads to the development of percolating network through the PNCs. These factors boost the dielectric permittivity values substantially, owing to the decrease in the nano-confinement phenomenon. The rise in applied frequency reduces dielectric permittivity and impedance values and enhances ac electrical conductivity. These PNCs having good dielectric and electrical characteristics can be used as frequency tunable nanodielectric material in electronic devices.

Characteristics of PEO Incorporated with CaTiO3 Nanoparticles: Structural and Optical Properties

In this research, direct band gap polymer composites with amorphous phase, which are imperative for optoelectronic devices applications were synthesized. The solution cast technique was used to produce polyethylene oxide (PEO)/calcium titanate (CaTiO3) nanocomposite (NC) films. The X-ray diffraction (XRD) confirms the growth of amorphous nature within PEO with CaTiO3 addition. The optical band gaps of pure PEO and PEO/CaTiO3 NC films were calculated using analysis of ultraviolet–visible (UV-Vis) spectra. The change in absorption edge toward lower photon energy is evidence of polymer modification. The dispersion behavior of the refractive index of PEO was manipulated to a higher wavelength upon doping with CaTiO3. Upon adding CaTiO3 to the pure PEO polymer, the dielectric constant and refractive index were considerably modified. The band gap shifts from 4.90 eV to 4.19 eV for the PEO incorporated with an optimum portion of 8 wt. % of CaTiO3. The types of the electronic transition in composite samples were specified, based on the Taucs model and the optical dielectric loss. The alteration of UV/Vis absorption spectra of the NC film was considered a suitable candidate to be applied in nanotechnology-based devices. The spherulites ascribed to the crystalline phase were distinguished through the optical microscopy (OM) study.

Electrical and Optical characterization of Malonic acid doped Poly Vinyl Alcohol polymer electrolytes

Novel proton conducting solid polymer electrolyte membranes based on Poly vinyl alcohol (PVA) with Malonic Acid as dopant are prepared by solution cast technique with varying doping concentrations up to 40 wt.%. The electrical conductivity and optical absorption of pure PVA and Malonic aciddoped PVA electrolytes are investigated. DC conductivity behavior is studied in the range 303K to 373K. It is found that PVA: Malonic acid (70:30) electrolyte exhibits the maximum conductivity. The electrical conductivity initially increases with increasing dopant concentration and then showed a decrease beyond 30 wt.% concentration. The increase in conductivity is attributed to formation of charge transfer complexes while the decrease for concentrations above 30 wt.% is due to segregation. Optical absorption studies are made in the wavelength range 200-600 nm and the values of optical band gap (direct and indirect) are estimated. The results obtained are presented and discussed.

Secondary Dopants of Electrically Conducting Polyanilines

Secondary dopants and the doping methods were identified for increasing the electrical conductivity of a highly processable and a primarily doped polyaniline dinonylnaphthalene sulfonic acid (PANI-DNNSA). The secondary doping was carried out using film, solution, and vapor doping methods. The doping methods and functional groups of secondary dopants were observed to play a critical role for inducing electrical characteristics of polyaniline. When secondary film doping method and p-toluenesulfonic acid were used, the electrical conductivity of the secondary doped polyaniline was measured to be increased from 0.16 to 334 S/cm. A novel vapor annealing doping method was developed to incorporate secondary dopants into solution cast polyaniline films.

Thermal, Structural and Morphology Studies of PEO-LICF3SO3-DBP-ZrO2 Nanocomposite Polymer Electrolytes

This work represents thermal study of PEO-based polymer electrolyte films that were prepared by the solution cast technique. The melting temperature Tm, glass transition temperature Tg and degree of crystallinity χc were measured by diffraction scanning calorimetry (DSC). Thermogravimetric (TGA) was used to determine the initial and final degradation temperatures. The structural was also performed to characterize the vibrational wavelength and phase characteristic (crystalline/amorphous). While the morphological study was emphasized to examine the features appearance for pure polymer electrolyte system as well as after addition salt, plasticizer and filler. The zirconium oxide particles were measured after the milling process by using the transmission electron microscopy (TEM), and the particles obtained in the range of 9 – 54 nanometer size.

Influence of poly(ethylene oxide) sample preparation on the results of thermogravimetric analysis

Aim: To investigate whether the sample preparation process of poly(ethylene oxide) (PEO) affects kinetic analysis of the thermal degradation process. Kinetic analysis was performed to describe the course of a chemical reaction regardless of the reaction conditions and the reaction system complexity. One differential method, the Friedman method, and one integral Kissinger-Akahira-Sunose method (KAS), were applied in this work. Methods: The PEO sample was prepared in 4 different ways. Thermogravimetric analysis was performed to determine the thermal degradation of prepared samples. Infrared spectroscopic analysis was performed during the preparation of the PEO film obtained by casting from the solution. Results: Dynamic thermal decomposition of PEO, regardless of the method of preparation, takes place through a single decomposition stage, which is manifested by the appearance of one peak on derivative thermogravimetric (DTG) curve. During the preparation of the PEO film, the procedure was carried out at a temperature higher than its melting temperature (Tm=65°C). After the cooling, the obtained sample didn’t solidify and it had an intense odor of acetic acid, which was confirmed by infrared spectroscopic analysis. Samples III and IV were re-prepared at a temperature lower than the melting point of PEO, obtaining samples of satisfactory quality. Conclusion: In order to prepare poly(ethylene oxide) films by solution casting technique, drying should be carried out at temperatures below the melting point of PEO. If TG analysis of pure PEO powder is compared with the results of hot pressed samples and solution cast samples, it can be concluded that the preparation of the sample doesn’t affect the thermal stability of the PEO. The dependence of activation energy calculated by the differential Friedman and integral KAS method on conversion is constant for all samples in a broad conversion range, regardless of how the samples were prepared. The hot pressed samples and solution cast samples have lower activation energy than the commercial PEO powder.

Mechanistic Study on Gold-Like Luster Development of Solution-Cast Oligo(3-methoxythiophene) Film

Solution-cast coating films of perchlorate-doped oligo(3-methoxythiophene) exhibited a gold-like luster similar to that of metallic gold despite the involvement of no metals. However, the development mechanism of the luster remains ambiguous. To understand the mechanism, we performed scanning electron microscopic analysis, variable-angle spectral reflectance measurements, and ellipsometry measurements on ClO4−-doped oligo(3-methoxythiophene) cast film with a gold-like luster. The results revealed that the lustrous color of the film was not induced by the submicron-sized regular structures (structural color), nor by the high-density free electrons (reflective response based on Drude model), but by the large optical constants (refractive index and extinction coefficient) of the film, as speculated previously.

Investigation of morphology and transport properties of Na+ ion conducting PMMA:PEO hybrid polymer electrolyte

The aim of this research work is to examine the modification of structure, morphology and conductivity properties of PMMA: PEO blend hybrid polymer electrolyte system complexed with NaClO4 salt. Solution-cast procedure was adopted in preparation of these films. These films were characterized with XRD, SEM, DSC, and DC conductivity for the evaluation of modified properties. Peaks have disappeared and broadened in the XRD pattern of PMMA for higher concentration of PEO polymer and salt presented films, which indicated that attaining of higher amorphous phase in these polymer electrolyte films. Almost smooth surface morphology with fewer pores was observed in 20 wt. % of PEO and NaClO4 salt present PMMA films of SEM image. This establishes a dominant presence of amorphous content in these NaClO4 complexed PMMA:PEO hybrid electrolyte films when compared to pure PMMA and PEO. Disappearance of melting temperature was observed in all concentrations of NaClO4 salt and PEO polymer added PMMA polymer films, which suggests a decrease of crystalline and an increase of amorphous nature. Enhancing of DC conductivity with temperature was observed in all the films but higher conductivity was exhibited at higher concentration of NaClO4 salt present films.