Multilayers interdigitation

Zhu, M. Jiang, Z. Jing, W. Fabrication of polypyrrole-glucose oxidase biosensor based on multilayered interdigitated ultramicroelectrode array with containing trenches. Sens. Actuators B Chem. 2005, 2, 382-389. 

To implement this strategy, multilayered semiconductor structures were grown by MOCVD and then processed using lithographic techniques to create trenches of 10-20 p-m. Trenches of 10 pm were used to create arrays of 34 interdigitated LED/photodiode pairs, as shown in Fig. 8. As molecules adsorb onto the surfaces of these semiconducting materials, the electronic properties of the surfaces can be altered and thus changes in current can be observed when molecules such as ammonia and sulfur dioxide adsorb onto the surfaces of the diodes. 

ID ordered lamellar phases are known as gel states, and occur when phospholipids are arranged into bilayers that then stack into a multilayer with each bilayer separated by water. The fatty acid alkyl side-chains are stiff and extended, as in the 3D and 2D lamellar crystal phases, but may undergo hindered rotations about their chain axes. There are a number of types of ID ordered lamellar phases depending upon the tilt angle 0 these are (0 = 0), (0 > 0) and an interdigitated phase L i (0 = 0) where fatty acid alkyl side-chains from different monolayers overlap with each other (Figure 1.91). One other ID ordered lamellar phase, Lg, is known, in which the fatty acid alkyl side-chains cease to be linear but adopt a helical conformation. 

A new slide-off transfer printing method of fabricating multilayer sensors is shown in Figure 1.6. Typically, the oxide films were separated from the mount paper by soaking them in water before they were transferred on the alumina substrates. After that, they were printed with interdigitated Pt electrodes (the gap between electrodes was... 

The bulky bridged structure reduces intermolecular interactions in comparison to other PPVs. Multilayer films are deposited onto silicone substrates with interdigitated gold electrodes. 

Unlike commonly applied interdigital multilamination approach, split-and-recombine (SAR) mixing relies on a multiste p procedure. According to its name, the basic operations are the splitting of a bi- or multilayered stream perpendicular to the lamella orientation into substreams and their subsequent recombination [33]. This concept is schematically represented in Figure 4.19a. For this purpose, basically three steps are required flow splitting, flow recombination, and flow... 

A pH sensor, based on a.c. conductivity measurements of a thin polymer film, has been developed. The sensor consists of a planar interdigitated electrode array coated with a polypyrrole multilayer, built-up using the Langmuir-Blodgett technique. Impedance spectroscopy has been used to investigate the complex admittance of the device when exposed to aqueous solutions of different pH. The experimental data have been fitted to the theoretical response of an equivalent electrical network of capacitors and resistors. A response over the pH range 3.5 to 8 has been measured. 

To understand the sensor response, two devices were studied the uncoated interdigitated gold electrode and the electrode structure covered with the polypyrrole multilayer. 

From the fitting, this has a value of 36 pF (slightly greater than obtained with the uncoated electrode). Rppy represents the in-plane resistance of the polypyrrole-palmitic acid film, which from the curve fitting is found to be 3030 Q. The capacitance of the polypyrrole multilayer coated interdigitated electrodes measured in vacuum was only a few pF has been ignored in the model. 

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