Micro-conductivity sensors

Experiments were conducted to measure the stiffness of an IPMC beam and two IPMC-PVDF composite beams with different insulating layer thickness (30 pm vs. 100 pm). The two composite beams were named IPMC/PVDFl and IPMC/PVDF2, respectively. As illustrated in Fig. 8.5(a), the cantilevered beam under measurement was pushed quasi-statically at the tip by a linear actuator. Between the linear actuator and the tip was a PVDF-based micro force sensor measuring the interaction force. The tip displacement was measured with a laser distance sensor. Fig. 8.5(b) shows the measured tip displacement together with the corresponding force for each beam, with the spring constants determined to... 

Experiments were conducted to characterize the micro-force sensor. The IPMC-PVDF sensory actuator with integrated bending and force measurement was enclosed in a conductive shielding box, with its end-effector, a needle, protruding out of a slit on the box. To emulate the force level typically encountered in bio and micro applications, soap bubbles were pierced with the end-effector. The experimental setup is shown in Fig. 8.21(a). Fig. 8.21(b) shows the force sensor output when a bubble was moved man-... 

Afridi MY, Suehle JS, Zaghloul ME, Tiffany JE, Cavicchi RE (2001) Implementation of CMOS compatible conductance-based micro-gas-sensor system. In Proceedings ECCTD Ol, European conference on circuit theory and design, Espoo, Finland, 28-31 Aug, pp 381-384... 

Fang, Q., Chetwynd, D. G., Covington, J. A., et al. (2002) Micro-gas-sensor with conducting polymers. Sensors and Actuators B Chemical 84, 66-71. 

Wilson SA, Jourdain RPJ, Zhang Q et al (2007) New materials for micro-scale sensors and actuators an engineering review. Mater Sci Eng R Rep 56 1-129 Wu Y, Zhou D, Spinks GM, Irmis PC, Megill WM, Wallace GG (2005) TITAN a conducting polymer based microfluidic pump. Smart Mater Struct 14 1511-1516 Wu Y, Alici G, Spinks GM, Wallace GG (2006) Fast trilayer polypyrrole bending actuators for high speed applications. Synth Met 156 1017-1022... 

For micro PS a decrease in the specific resistivity by two or three orders of magnitude is observed if the dry material is exposed to humid air [Ma8] or vapors of polar solvents, e.g. methanol [Be6]. This sensitivity of PS to polar vapors can be used to design PS-based gas sensors, as discussed in Section 10.4. This change in resistivity with pore surface condition becomes dramatic if the pores are filled with an electrolyte. From the strong EL observed under low anodic as well as low cathodic bias in an electrolyte it can be concluded that micro PS shows a conductivity comparable to that of the bulk substrate under wet conditions [Ge8]. Diffusion doping has been found to reduce the PS resistivity by more than five orders of magnitude, without affecting the PL intensity [Ell]. 

Fibre optic-based flow-through optical biosensors The dramatic advances in fibre optic development in die last decade have promoted construction of sensors where radiation, whether emitted, transmitted or reflected, is conducted fi-om the sample to the detection system. The wide variety of available optical waveguide types (solid rods, hollow cylinders, micro-planar geometries) has been used with varying success in sensor development. 

Lang, Th.. Caron. M.. Izquierdo. R.. Ivanov, D., Currie, J.F. and Yelon. A. (1996) Material characterization of sputtered sodium-ion conductive ceramics for a prototype CO2 micro-sensor. Sens. Actuators B, 31, 9—12. 

As opposed to inertial sensors, micromachined anemometers are often based on micro hot plates, that is, combinations of heaters and thermometers on thermally insulating membranes or multilayered thin films [4]. Functional sensor parameters are obviously determined by thermal conductivities and heat capacities, which can be monitored to reject faulty chips. Until recently, suitable wafer-level testing methods have not been available, and most sensor designs were based on literature values, despite the fact that these values depend strongly on fabrication processing parameters. 

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