Conducting polymer patterns

The fabrication of a conducting polymer pattern is considered to be one of the most important subjects in the field of molecular electronic devices. A novel photo-sensitized polymerization of pyrrole was investigated, in order to form fine conducting polymer patterns... 

Even though conducting polymers have many advantages such as flexibility and relatively low cost, the complicated methods necessary to obtain customized conducting polymer patterns are obstacles in many applications. Especially in disposable electronics, the number of processing steps and chemicals should be minimized. It was reported that a novel method for the preparation of patterns, called Line Patterning, could produce a PPy pattern with an acceptable resolution [122]. In line patterning, PPy... 

Fig. 23-2 Procedure for the formation and transfer of electrically conductive polymer patterns onto insulating substrates. Step A application and development of patterned photoresist on the gold over mica substrate. Step B electrodeposition of electrically conductive polymer onto the exposed gold surface. Step C application of the adhesion promoter. Step D application of the insulator onto the adhesion promoting layer. Step E removal of the mica by immersion in dilute hydrofluoric acid solution. Step F etch removal of the gold layer by immersion in aqueous KI/I2 solution. Step G dissolution of residual photoresist in acetone. After Reference [955], reproduced with permission.

Yoon el al. [112] reported an all-solid-state sensor for blood analysis. The sensor consists of a set of ion-selective membranes for the measurement of H+, K+, Na+, Ca2+, and Cl. The metal electrodes were patterned on a ceramic substrate and covered with a layer of solvent-processible polyurethane (PU) membrane. However, the pH measurement was reported to suffer severe unstable drift due to the permeation of water vapor and carbon dioxide through the membrane to the membrane-electrode interface. For conducting polymer-modified electrodes, the adhesion of conducting polymer to the membrane has been improved by introducing an adhesion layer. For example, polypyrrole (PPy) to membrane adhesion is improved by using an adhesion layer, such as Nafion [60] or a composite of PPy and Nafion [117],... 

One of the most important applications of nanoporous membranes is as nanoscaffolds in template synthesis, to replicate the structural features of the nanopores, or patterns, into metals [233], carbons [234], semiconductors [235,236], conductive polymers [237,238], and other materials [239]. The important characteristics of template synthesis have been best reviewed by Martin [188,240]. In short, it is a robust, general method suitable for the... 

A generalised structure of an electronic nose is shown in Fig. 15.9. The sensor array may be QMB, conducting polymer, MOS or MS-based sensors. The data generated by each sensor are processed by a pattern-recognition algorithm and the results are then analysed. The ability to characterise complex mixtures without the need to identify and quantify individual components is one of the main advantages of such an approach. The pattern-recognition methods maybe divided into non-supervised (e.g. principal component analysis, PCA) and supervised (artificial neural network, ANN) methods also a combination of both can be used. 

In addition to the conventional lithographic techniques, surface patterning was performed by means of local polymerisation of the monomers under the SPM tip. These studies have been mainly focused towards electrically conductive polymers such as polypyrole, polythyophene and polyaniline. The easiest way to implement polymerisation is to set either the tip or sample potential sufficiently positive to cause the electrochemical oxidation of the monomer [438, 451 -455]. This technique enabled controlled removal and deposition of polymer dots as small as 1 nm to in a well defined pattern [453]. After deposition, the dots could be read using a conventional imaging mode (Fig. 49). 

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