No description available.

Electroactive, or 'conductive', polymers are a rapidly expanding area of research with proposed applications ranging from batteries or electronic circuitry to artificial muscles and actuators. An emerging application for these materials is as constituents of corrosion resistant coatings. An important factor in any corrosion resistant coating is the level of porosity it possesses. Minimisation of porosity may be highly desirable for the production of highly protective films. This work aims to study methods for controlling the porosity of polypyrrole films for their possible use as corrosion resistant coatings. It has been observed that surfactants can modify the structure and morphology of polypyrrole on inert substrates such as platinum or indium-tin oxide glass, and on the non-inert substrate mild steel. This has involved the study of the conditions necessary for polymer deposition on mild steel where the tendency for metal dissolution competes with the polymerisation reaction. Corrosion studies were carried out, firstly, to assess the corrosion potentials for such films and, secondly, via Tafel extrapolation to determine the effects of film thickness and anionic surfactant concentration on the corrosion rates obtained. Further corrosion studies were performed on polypyrrole films with additions of molybdate corrosion inhibitor species and anionic surfactants. It was found that polypyrrole with additions of anionic surfactants had little or no effect on the corrosion characteristics of mild steel in saline environments. However, in the presence of molybdate and certain levels of surfactants, excellent corrosion resistance characteristics were observed. It is proposed that the reduction of polypyrrole occurs at large negative corrosion potentials, resulting in the formation of an insulating polymer film that is incapable of acting as a site for displaced corrosion reactions around which many of the theories of electro active polymer corrosion protection have previously been based.

Conductive ink from a printer allows for the fabrication of conductive material with tight tolerances without the cost and time of chemical etching. This paper explores the use of AGIC printable conductive ink on a paper substrate as design tool for antennas as well as classroom use in antenna education. The antenna designs satisfy the requirements of a compact Global Navigation Satellite System (GNSS) antenna while showing a competitive performance within the current market. One best design is shown along with three other structures. These antennas consist of a bowtie cross-dipole over a reflective disc with conductive-ink grounded structures. In addition to the GNSS antennas, a linear elliptical dipole over a reflective disc with conductive grounded structures is presented. This elliptical antenna design attempts to find the maximum impedance bandwidth beyond the GNSS band. The inexpensive nature of conductive ink allows for its use in a classroom to demonstrate antenna behavior as part of antenna education. An inexpensive approach to the patch antenna using conductive ink is described and paired with a system made of off-the-shelf parts. The system is capable of measuring the power of the received signal. The received signal measurement is not as accurate as using a anechoic chamber but pattern details are visible. This is used to demonstrate aspects of the Friis transmission equation such as distance, polarization, radiation pattern shape, and loss.

Human disease processes are often characterized by a deviation from the normal physiological concentration of critical biomarkers. The detection of disease biomarkers requires the development of novel sensing methods which are sensitive, specific, efficient and low-cost. To address this need, a novel conductive and recognitive hydrogel composite material has been developed. This work investigated the fabrication methods, the chemical and physical composition, the sensing capabilities, and the biocompatibility of the proposed conductive and recognitive hydrogel composite materials. The conductive polymer was found to respond by changing conductivity in the presence of biomolecules. Specificity can then be incorporated into the system by integrating the conductive polymer with a molecularly imprinted hydrogel. The demonstration of a conductive and recognitive hydrogel composite is a step towards the integration of these materials into close-loop sensing and drug delivery systems. / text

No description available.

No description available.

Conductivity and electron spin resonance measurements have been performed on solution doped polyaniline (PANi). It is proposed that both camphor-sulphonic acid (CSA) and 2-acrylamido-2-methyl-l-propanesulphonic acid (AMPSA) doped PANi can be described by the same model. It is suggested that the polyaniline materials are composed of differently ordered layers, a highly ordered region forming the core of the crystallites. The core of the crystallites are believed to be encapsulated within a semi- ordered region, with the crystallites themselves being dispersed in an amorphous polymer matrix. The conductivity measurements and ESR results described in this work support the proposal that within the highly ordered region of doped polyaniline crystallites, a polaronic lattice exists. The polaronic lattice facilitates "free" carriers which are responsible for "metallic" conduction within the crystallites. Encapsulating the polaronic lattice is a semi-ordered region in which (partially) mobile polarons (and possibly bipolarons) are present. The highly conductive crystallites are randomly dispersed in a less conductive polymer matrix. Charge transport within this heterogeneous system is well described by a heterogeneous metal - fluctuation induced tunnelling (FIT) model. The differences in the temperature dependent conductivities of the PANi-CSA and PANi-AMPSA materials are attributed to the systems having layers of different relative sizes (in the above model). AMPSA doped polyaniline films had a maximum room temperature conductivity of ~100 Scm(^-1). This material also showed potential for use as an electrode layer in polymer LEDs, to replace ITO coated glass. The conductivity of PANi-AMPSA was measured to be 50 ± 10 Scm(^-1) at thickness' of ~30nm. Layers of this thickness provide >90% optical transmission between 450 and 675 nm (most of the visible spectrum). Faraday rotation measurements have shown that the recently reported large Faraday rotation of polyaniline can not be reproduced. The limited results of the Faraday rotation experiments described in this work provide support for the theory that charge carriers in polyaniline have an effective mass of at least 100 times that of a free electron. It has also been shown that the claims of a polyaniline derivative (namely the Marcoussis polymer) being an entirely organic ferromagnet are unsubstantiated, despite intense investigation.

Abstract: The carbon black material used as reinforcing filler in tires was recovered by pyrolysis at a temperature of 490¢XC and at atmospheric pressure. The pyrolytic carbon black obtained (CBp) was contamined by various additives of the original tire. Contaminants were also produced by chemical reactions occurring in the pyrolysis reactor. The recovered carbon black was performed and a possible reduction of the ash content by hydrochloric acid treatment. After the demineralization treatment, the recovered pyrolytic carbon black (CBP) was heated in a post-pyrolysis process at temperatures ranging from 670 to 1170 ¢XC. The CBP were studied by low-pressure nitrogen adsorption and surface spectroscopic method ( SIMS), Raman spectroscopy, XRD, TPD, TEM. Furthermore, the CBP properties were correlated to their electrical conductivities.

Electromagnetic shielding materials for plastic packaging in laser modules application were studied experimentally. Bipheny1, Nylon and LCP mixed with Al-powder, Al-flake, carbon-fibers and steel-fibers was fabricated and measured in shielding effectiveness(SE) for EMI. Compression molding, double-screw extrusion and injection molding were used for fabrication. We examed the mechanical properties and shielding effectiveness of these compounds. The SE of conductive plastics was measured to be 40dB at 30MHz and 60dB at 1GHz for carbon-fiber and plastic mixture. The experiment result indicates that introducting conductive carbon fiber fillers into plastics will produce conductive composites having an excellent SE to reduce EMI. With these excellent SEs, such conductive carbon fiber fillers into plastics are suitable for use in low-cost laser modules.

Abstract The Nylon and liquid crystal polymer(LCP) filled with conductive carbon fiber applied to 155Mbps and 1.25Gbps transceiver modules for electromagnetic(EM) shielding were studied. The measured results showed that the shielding effectiveness(SE) of 155Mbps and 1.25Gbps transceiver module were 13dB and 20dB to conform to FCC class B standard, respectively. This indicates that the plastic housing filled with conductive carbon fiber is suitable for EM shielding in plastic laser transceiver module applications.