One of the exciting developments in material science today is the design and synthesis of polymer nanocomposites (PNC) containing electrically-conductive polymer and mesoporous MCM-41 that possess novel properties not exhibited by the individual organic and inorganic materials. The physicochemical and conductingproperties of two types of PNC namely, PEO/Li-MCM-41 and PANI/MCM-41 prepared by melt and solution intercalation and in situ polymerisation methods have been investigated in this thesis. The aim was to obtain a more detailed understanding of how the combination of polymers with the mesoporous MCM-41 is related to the conductingproperties of the PNC. Before PEO and PANI are combined with MCM-41, several modifications of MCM-41 have been done including ion exchange of MCM-41 with lithium chloride, silylation of MCM- 41 with trimethylchlorosilane (TMCS) and functionalization of MCM-41 with sulfonic acid. The PNC obtained was characterized by X-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimetric analysis and chemical analysis, followed by 27 Al, 7 Li and 13 C/CP MAS NMR spectroscopy. It is confirmed that the
Currently, the research work is focused on the development of blend polymer with better conductivity for fuel cell and batteries related application. As the physical and chemical properties of both the polymer chain are different, the resulting blend is entirely unique with the possibility to improve the conducting nature. Many blend polymer electrolyte system have been studied and reported in the literature [3-5] . It is seen from the literature that blending of two polymers improved the conductivity of the
Since last decade, biotechnology domain has offered many open research issues. This led to significant developments all over the world. High quantum of work has been proposed for solid state electronic circuits. Electronic circuit realization using conductivity of liquid medium is the key issue now a day. The research has been focused to get the stable result from the aforesaid circuit using different feasible apporoaches. One of the feasible approache has been aaplied here to demonstrate the basic monostable multivibrator circuit. The result shows strong possiblility to develop liquid electronic circuit. Here, the author has systamatically replace each solid component using liquid medium and finally designed liquid circuit. The syntheic plasma has been formed in the laboratories to be used as conducting liquid. Power supply and analog input signal has been applied to the circuit by conventional power supply generator and function generator respectively. The response from the circuit has been observed in cathore ray ossilloscope. Similar kind of circuit could be investigated using human implantable material.The presented biological electroic circuit has a potential to work as an implantable circuit for humanbody. These kind of circuits are effectvely utilised for cyborg implants/engineering, man-machine interface, human disease detection and healing, artificial brain evolution in biotechnology domain.
Several techniques have been used to prepare ZnO such as pulsed laser deposition (PLD) 1 , molecular beam epitaxy (MBE) 2 , DC Magnetron sputtering 3 , metal organic chemical vapour deposition (MOCVD) 4,5 , spray pyrolysis 6-8 , hybrid beam deposition(HBD) 9 and sol-gel technique 10 . Sol-gel process is known to have the distinct advantage of simple process and easy control of the film composition especially uniform thickness. Thin films of undoped ZnO were prepared on glass substrate at different post annealed temperatures. UV-Visible measurements for transmittance and absorption have been carried using Varian Cary 5E spectrometer. Scanning Electron microscope (SEM) measurements were performed to characterize the surface morphology, using FEI quanta FEG HR-SEM. Conductivity and temperature dependent conductivity studies were carried out to understand the electrical properties. FT-IR was recorded using PE FTIR in order to establish the inter-atomic bonding that enables effective conductivity. In this paper we report sol –gel technique to prepare zinc oxide annealed thin film for effective photo conducting by spin-coating.
Polymers are generally known as insulators. Polymers are simply very large molecules (macromolecules) that are made up of smaller molecules (monomers) that can be linked together in various ways, resulting in a range of what we call microstructures (e.g. linear chains, branched chains, densely interconnected networks etc.). Plastics that conduct electricity have been around since 1970's, but their electronic properties, and widespread use, have been limited by structural disorder. Polymers are a shiny material derived from acetylene, whose electrical conductivity surpassed those of conductors. The oxidation of Polyacetelene with Iodine, using Ziegler-Natta-catalyst yielded this material. Large efortts have been taken during the past two decades in the understanding of the chemical, electrochemical, structural, electrical and optical phenomena of inherently conducting polymers, such as polypyrrole (PPy), polythiophene (PT), polyaniline (PANI), polyphenylene (PPh) and their derivatives [1-3]. The great interest in these polymers arises from their relative ease of synthesis by chemical or electrochemical oxidative polymerisation of the monomers and from their considerable importance as candidates for new materials that would lead to the next generation of electronic and optical devices and as promising transducers for chemo or bio- sensors [1-11]. The fact that the 2000 Nobel Prize in Chemistry went to Alan J. Heeger, Alan G. MacDiarmid and Hideki Shirakawa “for the discovery and development of conductive polymers” (Nobel Citation) also reflects both research and practical importance of conducting polymers and their applications in modern science and daily life. This new conducting polymer is being used in anti- static and anti-corrosive materials, electronic integrated circuits, photonics, displays, lasers, sensors, photovoltaics, actuators, and electromagnetic shielding. Compared to silicon technology, polymers are not only flexible, but cost less to manufacture [1-14]. Now polymers are amongst the most widely used materials in the modern world due to their diversified technological applications. The main advantage of these conduting polymers is that they exhibit conductivity ranging from insulator to conductor [15-16].
techniques. The data analysis showed an interfacial interaction between PANI and MZFO through the formation of core-shell structure and exhibited an increase in the thermal stability of PANI matrix with the addition of MZFO. The magnetic characterization indicated ferromagnetic behavior for MZFO and showed an improvement in the PANI magnetic properties by the addition of MZFO. The conductivity measurements as a function of temperature showed a decrease in the conductingproperties of PANI by the addition of MZFO and a consequent change in the electrical properties from metallic to semi- conducting behavior. Generally, the obtained results indicated the possibility of tailoring electromagnetic properties of PANI depending on the weight percent of MZFO.
In conclusion, polyaniline based binary and ternary hybrids were prepared and exhibited better luminescent and conductingproperties than polyaniline. Luminescent spectra of polyaniline and its hybrids were taken at differ- ent concentration in DMSO and found to be concentration dependent. Fluorescence signals of polyaniline and its hybrids were found to be aggregation caused quenching (ACQ) type. Powder X-ray diffraction pattern revealed that hybrids of PAni exhibit poor crystallinity than PAni. Ternary hybrid, PAni-PEG-As 2 S 3 , posses highest
PANI/ZnO Composite: The semi-crystalline structure of the synthesized nanocomposite of Polyaniline (PANI) and Zinc Oxide (PANI/ ZnO) was characterized by XRD. The recorded XRD pattern confirmed that synthesized composite of Polyaniline (PANI)/Zinc Oxide (ZnO) is polycrystalline that is semi amorphous in nature. Figure 3 shows XRD pattern of zinc oxide nanoparticles and that of various nanocomposites showed similar peak patterns, therefore, it may be assumed that presence of polyaniline did not cause any change in crystal structure of zinc oxide or negligible change which may be ignored 24,25 . These results show that polyaniline present in nanomatrix is amorphous in nature which supports the previous reports. Moreover above discussion also supports that the incorporation of supporting polymer into polyaniline does not affect the crystal structure of ZnO. However, presence of such polymers seems to cause the decrease in the size of ZnO nanoparticles this is due to formation of polymer-Zn complex on the surface of ZnOnanoparticles present within/on the surface. This superficial property of the nanocomposites as has also been suggested by Tanget al 26 in the study of x-rays patterns of Polymethylmethacrylate (PMMA) and zinc oxide composites. Scanning Electron Microscopy Studies: SEM of Polyaniline (PANI): Scanning Electron Microscope (SEM) images of selected sample was obtained using SEM-JEOL 840 A. The surface morphology of nano size Polyaniline by SEM and its micrographsare shown in figure 4 (a,b). From SEM image PANI is more porous in nature. Due to small pores size, its surface area is more which helps to enhance properties.
As we known, uric acid (UA) is the primary final product of purine metabolism in the human body, and is excreted via urine . It is of biomedical significance, and plays determining roles not only in human metabolism but also in the central nervous and renal systems. Abnormal levels of UA are symptoms of several diseases such as gout, hyperuricaemia and Lesch-Nyhan syndrome. UA is also a risk factor for leukemia, pneumonia and cardiovascular disease [5,6]. In addition, numerous reports have shown FA and UA usually co-exist biological systems and that they influence each other in their respective activities [7,8]. Therefore, investigation of neurological behavior and also simultaneous determination of FA and UA is of great importance for the elucidation of their precise physiological functions. Due to interesting electrochemical properties of FA and UA, application of the modified electrodes is considered as the common routes in this area. However, ascorbic acid (AA) is always coexisting with FA and UA in the extra cellular fluid of the central nervous system and serum. Therefore, simultaneous determination of FA and UA in the presence of AA is an important issue not only in diagnostic and pathological research but also in the field of biomedical chemistry. The electrochemical response of AA will certainly interfere in the detection of FA and UA under coexistence of AA on conventional electrodes. To resolve this problem, various chemical modification of electrode surface have been made for the determination of FA and UA in the presence of AA.
This paper reports the successful preparation hybrid modified electrode on Pt electrode surface (Pt/PABT/NiHcF) by repetitive CV scans, to improve the electrochemical behavior of the prepared modified electrode. The influence of several parameters e.g.electrolyte composition, scan rate and potential limits as well as their behavior in various alkali metal electrolyte. The electrocatalytic oxidation properties of some organic compounds e.g. MeOH and (COOH) 2 will be examined.
The size of Ag particles synthesized in the process of silver nanowire preparation is usually large. The particles are not completely removed by centrifugation. Even though using density gradient centrifugation, a small quantity of nanoparticles exists in silver nanowires and a lot of nanowires are lost. Therefore, the roughness and optical properties of silver nanowire films are affected, and the conductive and optical properties of the other particles of inoculating seed such as Pt, Fe, and Cu, are lower than Ag. In this paper, the synthesis of silver nanowires without nanoparticles and flexible transparent conducting thin film prepared is reported. In this typical synthesis process, silver nanowires are prepared by a modified traditional polyol process where glycerol is prepared instead of ethylene glycol in the presence of PVP and glycerol without other agents in the autoclave. Remarkably, the process is very simple to put mixed solution in autoclave one step at room temperature, and the obtained silver nanowires have no other particles and impurities. Thus, silver nanowires are successfully dispersed in the isopropyl alcohol after the purification. Then, firstly, the above silver nanowires are pumped on the cellulose membrane, which is pasted on the PET by the reciprocating rolling. After cellulose membrane was dissolved, the flexible transparent conducting thin film is prepared completely. Uniform silver nanowires can contribute to the stability of flexible transparent conducting thin film. In the end, the properties of the synthesized silver nanowires and the flexible transparent
sites in the conventional unit cell of eight formula units. In order to understand the fast Li + transport properties in lithium stuffed garnets a knowledge of difference in the distribution of lithium between conventional garnet and that of lithium stuffed garnets is necessary. Owing to the limitations of X-ray diffraction towards lithium there exists an uncertainty in the determination of occupancy of lithium in the available tetrahedral and octahedral sites. Lithium arrangement in lithium stuffed garnets was reliably predicted using neutron diffraction method. 17,
The present study investigates the performance of mustard oil biodiesel, measuring the fuel properties and conducting experimental analysisload characteristics of produced oil on vertical single cylinder diesel engine, model TAF 1 produced by Kirloskar Oil Engines. This engine has a compression ratio of 17.5:1. It has a power rating of 3.7 KW at 1200 rpm, 4 KW at 1500rpm, 5.7 KW at 1800rpm and 6.2 KW at 2000rpm.For varying loads and various blends of biodiesels with compression ratio (17.5:1) and injection pressure of 200 bar.
that the reflectance of Si reduces to about 4 to 5% on deposition of graphene on planar Si. Earlier, a reduction of about 70% in reflectance of Si has been reported to take place on deposition of graphene [21,34], although the thickness of graphene used was quite large (20 nm). Reductions of about 4 to 5% in the reflectance of planar Si on deposition of graphene in the wavelength range of interest are quite interesting. The difference in the simulated (Figure 4b) and experimental (Figure 4c) values is attributed to the deviation in the nature of ideal graphene layer used in simulation in comparison to that in the experiment. In the optical model for FDTD simula- tion, a wrinkle-free monolayer graphene deposited on the complete substrate area without the effect of the substrate is considered. However, it is well known that graphene obtained by any synthesis technique would have many defects in the form of wrinkles, ripples, ridges, folding, and cracks [35-37]. Additionally, some unwanted molecu- lar doping such as water molecules may also be present on the surface of graphene [38,39]. These factors can modify its optical properties and thus the reflectance of G/Si structure [21,34,40]. Furthermore, it is also reported that the amount of wrinkles, folding, and chemical doping in graphene depends upon the substrate onto which graphene is deposited or transferred . In an earlier study, it has been demonstrated that deposition of wrinkle-like graphene sheets exhibits a broadband light trapping effect in Al nanoparticles and graphene-based solar cells . Thus, the observed decrease in reflectance in G/Si samples in comparison to the change in reflect- ance in the simulated results can be due to such adsorbed molecules or because of the synthesis defects and wrinkles (Figure 5b) in graphene.
Current work proposes an inimitable composite, with great electrical conductivity and quite enhanced surface area, (including conducting polymers (poly (cathechol)), Cu 2 O–carbon dots and green synthesized gold nanoparticles) for detecting acute carcinoembryonic antigen. At current work, the electropolymerization was offered instead of enzyme-catalyzed polymerization of poly (catechol). Four cost-effective electrochemical techniques (Differential Pulse Voltammetry, Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Crono amperometry) were engaged to investigate aptasensors construction, immobilization, hybridization, sensitivity, selectivity, repeatability, long-term stability and real PCR sample detections. According to the data, the values of I peak is linearly related to the logarithm of the concentrations of carcinoembryonic antigen in the range from 1.0 pg mL -1 to 0.001 g mL -1 , with a detection limit of 0.19 pg mL -1 for
Our investigations revealed that the free electron concentration, n, is independent of temperature over the investigated range 20–320 K. Measurements for films with different thicknesses revealed that for films grown on Al 2 O 3 substrates the carrier concentration is decreasing with increasing film thickness, contrary to our expectations. This behaviour was observed in ZnO films grown on Al 2 O 3 substrates and is explained by the presence of a thin, degenerate, highly conducting interface layer between substrate and film.The results for films grown on SiO 2 show that the carrier concentration is increasing with increasing film thickness (Fig.3). This allows us to assume that most carriers in the highly conducting interface layer for the films grown on Al 2 O 3 are produced by Al diffusion from the substrate. RBS has a sensitivity for Al as low as 3%, not allowing the investigation of Al depth profile in our films.
In recent years, considerable attention was given to the uses conducting polymers. As one of the most important conducting polymers, polyaniline because of its chemical stability and relatively high conductivity and its derivatives have been extensively studied in different fields of science because of the demand for high performance materials in advanced technologies. In the current studies, polyaniline (PANI) and its composites with semiconductor was prepared chemical oxidation method in the presence of different bronsted acids from aqueous solutions. The effect of thermal treatment on electrical conductivity (DC, AC), and dielectric constant of the pure PANI, PANI+10% ZnO, PANI +15% ZnO and PANI +20% ZnO, conducting polymers were investigated. It is found that conductivity of PANI enhancing due to stretching polymeric chain cause due to interaction with ZnO.
It can be noticed that, the increase of ε″ with increasing temperature is higher compared to ε′. This is due to the contributions of three main factors to the relaxation phenomenon, namely, conduction losses, dipole losses and vibrational losses . At low temperature, dielectric losses are minimal as they depend on both ac resistivity and frequency. It is self-evident that as the temperature increases, the ac conductivity increases and so the conduction losses increase. Similarly, the ɛ' value eventually changes in the same way. The plateau of ɛ' and ɛ'' as a function of temperature can be ascribed to the fast reversal of the electric field at higher frequencies. Above 388 K, both ε′ and ε″ decrease with increasing temperature. It was reported that the remaining water inside polymers have a great effect on polymers physical properties. The most proper binding sites for water molecules in CS are the functional (OH and NH2) groups present in the polymer . Thereby, CS membranes are hydrophilic materials. Authors in Ref.  have argued that it is particularly hard to remove the absorbed water in polysaccharides, unless the samples temperature raised to about 361 K. As a consequence, the process of desorption of water at high temperatures led to the diminution of the adhesiveness between the membrane and electrode. On the other hand, at the low temperature, the adhesion could be plausible. However, a further increase in temperature has resulted in damaged of chitosan-based membranes and converting to a hard membrane as a result of water desorption. In this case the interfacial resistance between the membrane and the electrodes increases and thus increases the resistance of the membrane at the elevated temperatures, as a consequence both ε′ and ε″ drop.
CdO is one the promising transparent conducting oxides from II to VI group of semiconductors having high absorption and emission capacity of radiation in the energy gap. CdO has special features such as high conductivity, high transmission and low band gap made it applicable in photodiodes , phototransistors , photovoltaic cells , transparent electrodes , liquid crystal displays, IR detectors and anti reflection coatings . CdO thin films have been obtained by different techniques such as chemical bath deposition , SILAR , sol-gel , eletrodeposition , dc reactive sputtering , reactive vacuum evaporation process ,
and the inherent fluctuations on the characteristics of the individual wires. This calls for averaging strategies that reduce the impact of these fluctua- tions in any calculations, requiring a large amount of computational resources to determine the average sheet resistance for fixed nanowire properties, as was seen in chapter 3 . With that in mind, a novel method that processes Scanning Elec- tron Microscope (SEM) images of NWNs and captures the precise locations of all wires of a given sample was presented in chapter 3 . An example of an SEM im- age is presented in Figure 4 . 1 (a), and its digitised form is shown in Figure 4 . 1 (b). This establishes a benchmark connectivity the NWN possesses and removes the need for averaging over the wire locations, consequently reducing the fluctuations induced by spatial disorder. A matching connectivity profile for experiment and simulations allows for an extraordinary level of simplification in simulation and ex- periment comparisons. A further simplification can be made through a theoretical description of the electrical properties of a network giving a method to quickly esti-