Wire Imprinting

Microchannels were also wire-imprinted on Plexiglas using a 90-pm-dia. tungsten wire at 175°C. The channels were triangular-like, typically 200 pm wide 

Wire imprinting was also achieved on PS, PMMA, and a copolyester material (Vivak) using chromel wire [206], Low-temperature bonding was applied for channel sealing. The EOF was found to be the highest in the copolyester chip and the lowest in the PS chip. The chromel wire was stretched taut and placed 

FIGURE 2.21 Fabrication protocol for wire-imprinted devices [1011]. Reprinted with permission from the American Chemical Society. 

Instead of imprinting two cross-channels on two separate PMMA chips, the two wires have been stretched and crossed over on the same PMMA substrate for imprinting [207]. 

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Plastic channels could also be fabricated by the hot wire-imprinting method. A channel was imprinted on a piece of Vivak (copolyester) by a nichrome wire (50 pm dia.). It was clamped between the plastic and a glass slide (see Figure 2.21), and the assembly was heated at 80°C for 15 min. Then a perpendicular channel was similarly imprinted on a second piece of Vivak. The two pieces were then sealed at 75°C for 25 min (note that the two channels are not coplanar )[1011]. The channels were filled with water for storage [204,685]. 

Compare and contrast hot wire-imprinting and hot embossing for fabrication of polymeric chips [1011]. (4 marks)... 

Chen, Y.H., Chen, S.H., Analysis of DNA fragments by microchip electrophoresis fabricated on poly(methyl methacrylate) substrates using a wire-imprinting method. Electrophoresis 2000, 21, 165-170. 

Polymers are discussed as less-expensive alternatives to glass, in particular with respect to mass production of structures. Injection molding, hot embossing, wire imprinting, and laser ablation are among the technologies that were established to... 

A conductometric device for measurement of benzyltriphenylphosphonium ions was developed next [80]. Particles of benzyltriphenylphosphonium chloride-imprinted MAA-EDMA copolymer were held in a layer between two platinum wires using a filter paper. The device was exposed to the analyte in acetonitrile, an AC potential applied and the conductance recorded. The direct measurement principle is based on the enrichment of the analyte, a charged species, close to the electrode. A semi-linear response was observed between 1 mg/1 and 20 mg/1 (Fig. 18.4). In the two latter sensors it was anticipated that the effect of non-specific... 

The other type of impact printer we re going to discuss is the dot-matrix printer. These printers work in a manner similar to daisy-wheel printers, except that instead of a spinning, character-imprinted wheel, the printhead contains a row of pins (short sturdy stalks of hard wire). These pins are triggered in patterns that form letters and numbers as the printhead moves across the paper (see Figure 7.2). 

The shape that the SM actuator recovers to when heated is imprinted into the alloy by an annealing process. For instance, to fabricate a coil spring a SM wire is wound around a mandrel and annealed for 1... 2 hours at 350. .. 500 °C. Annealing temperature and duration have a strong influence on the actuators properties, such as the trainable two-way effect, the effect stability, and the hysteresis behavior. 

Gun J., Lev O. Sol-gel derived, ferrocenyl-modified silicate-graphite composite electrode Wiring of glucose oxidase. Anal. Chim. Acta 1996b 336(1-3) 95-106 Guo Y.Z., Guadalupe A.R. Screen-printable surfactant-induced sol-gel graphite coirposites for electrochemical sensors. Sensors Actuators B Chem. 1998 46(3) 213-219 Haupt K., Mosbach K. Molecularly imprinted pol3uners and their use in biomimetic sensors. Chem. Rev. 2000 100(7) 2495-2504... 

Figure 2.6 (a) Schematic of the metal wire-grid polarizer by depositing metal on topofthe roller imprinted polymer grating (b) SEM picture of a 200 nm period grating with 50 nm Al on top (c) spectral transmittance (TM, TE mode) and... 

AH initiation devices manufactured in North America are imprinted with a safety warning EXPLOSIVE-EXPLOSIF-DANGER-DETONATEUR-BLASTING CAP. Initiating devices typically are made of brightly colored plastic materials or wire insulation that may make them especially appeahng to children. In addition, initiation devices are quite small and can easily be concealed in a pocket or other small space. For these reasons it is particularly important to carefully maintain an accurate inventory of all initiation devices and to store them in appropriate, locked magazines separate from other explosives. 

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