Doping actuators

The electrocontractile response of a composite of a PVA-PAA gel doped with PPy has been investigated by a group in the University of Pisa [70], The composite strip (initial length 3.05 cm, thickness 0.016 cm) in a 0.05 N NaCl solution has acted as both an electrode and an actuator. When dc voltages up to 2 V were applied, PPy doped in the gel underwent a redox reaction to change the pH inside the gel, and the change in size was observed within 30 min. The measured length variation was about 2%. 

Suah F.B.M., Ahmad M., Taib M.N., Applications of artificial neural network on signal processing of optical fibre pH sensor based on bromophenol blue doped with sol-gel film, Sens. Actuat B 2003 90 182-188. 

S. H. Hahn, N. Birsan, and U. Weimar. Investigation of CO/CH4 mixture measured with differently doped Sn02 sensors . Sensors and Actuators B78 (2001), 64-68. 

After Little s proposal, many researchers have pursued such an exciting system in vain. Even metallic behavior was rarely seen in doped organic polymers, gels, and actuators. As mentioned in Sect. 3.4.4, MCso with linearly polymerized Ceo" exhibited one-dimensional (M = Rb, Cs) or three-dimensional (M = K) metallic behavior [144]. Recently a doped poly aniline was reported to exhibit a metallic temperature dependence for a crystalline polymer chemical oxidation of monomers grew crystallite polyaniline [329] early doping studies on polypyrrole (PFg) and poly(3,4-ethylene-dioxythiophene)X (X = PFg, BF4, and CF3SO3) prepared by electrooxidation at low temperatures also showed a metallic temperature dependence below 10-20 K (Scheme 16) [330, 331]. 

Su, L., Qiu, X. P., Guo, L. H., Zhang, F. H. and Tung, C. H. (2004), Amperometric glucose sensor based on enzyme-modified boron-doped diamond electrode by cross-linking method. Sensor Actuator B, 99(2-3) 499-504. 

Sharma, R.K. and M.C. Bhatnagar (1999). Improvement of the oxygen gas sensitivity in doped Ti02 thick films. Sensors and Actuators B-Chemical, 56(3), 215-219. 

Gonga H, Hu JQ, Wang JH, Ong CH, Zhub FR (2006) Nano-crystaUine Cu-doped ZnO thin film gas sensor for CO. Sens Actuators B Chem 115 247... 

Siemons, M. Simon, U., Preparation and gas sensing properties of nanocrystalline la-doped CoTi03, Sens. Actuators B 2006, 120, 110-118... 

Carotta, M. C. Guidi, V. Malagu, C. Vendemiati, B. Zanni, A. Martinelli, G. Sacerdoti, M. Licoccia, S. Vona, M. L. D. Traversa, E., Vanadium and tantalum-doped titanium oxide (TiTaV) a novel material for gas sensing, Sens. Actuators B 2000, 108, 89-96... 

Chakraborty, S. Sen, A. Maiti, H. S., Selective detection of methane and butane by temperature modulation in iron doped tin oxide sensors, Sen. Actuators B 2006,115, 610-613... 

One of the more fascinating applications is the electromechanical actuation with CPs, leading to artificial muscles, wings, and propellers. The basis behind such actuation is that CPs swell on doping, with an increase... 

FIGURE 3.16 Sensitivity to the different gases of the Tb-doped YSZ-SE deposited on a sapphire substrate versus a Pt counterelectrode at 600°C in flowing air. (Reprinted from Brosha, E.L. et al., Mixed potential NO sensors using thin film electrodes and electrolytes for stationary reciprocating engine type applications, Sens. Actuators B Chem. 119 (2006) 398-408, with permission from Elsevier Science.)... 

It has been established that when polyelectrolytes are incorporated as dopants in PAn, the switch from conducting to nonconducting material is shifted to very-high-pH solutions, enabling electrochemistry to be carried out on PAn in neutral solutions.37 Poly(methoxyanilines) have been used as the basis of electromechanical actuating changes in dimensions in the thickness direction of more than 20% were reported as the polymers are doped and dedoped.38-39 Similar effects are observed if some level of self-doping is introduced into the PAn backbone.40... 

Maekawa T, Anno Y, Tamaki J, Miura N, Yamazoe N, Asano Y and Hayashi K 1993 Development of semiconductor gas sensors to discern flavors of consomme soup Sensors Actuators B 13-14 713-14 Varfolomeev A E, Volkov A I, Eryshkin A V, Malyshev V V, Rasumov A S and Yakimov S S 1992 Detection of phosphine and arsine in air by sensor based on Sn02 and ZnO Sensors Actuators B 7 727-9 Hafele E, Hardtl K-H, Muller A and Schonauer U 1991 Semiconductor for a resistive gas sensor having a high response speed doped perovskite US Patent 4988 970... 

Zinc oxide, ZnO, is a p-type semiconductor and shows piezoelectric properties which make this material useful for microsensor devices and micromachined actuators [69, 70]. The Al-doped material is used as a transparent electrode [71]. Other applications of ZnO include gas sensors [72], solar cell windows [73] and surface acoustic devices [74]. The organometallic compounds diethylzinc, ZnEt2 [75-77], and dimethylzinc, ZnMe2 [78], are frequently used as precursors for the deposition of zinc oxide. However, these reagents are highly pyrophoric and tend to react prematurely in the presence of water or oxygen. If ZnEt2 is combined with an alcohol in the reaction chamber, stable intermediates, presumably zinc alkoxides and/or alcohol adducts, are formed in the vapor-phase [79]. These compounds are more stable than dialkyl zinc rea-... 

M.C. Carotta, M. Feironi, D. Gnani, V. Guidi, M. Merli, G. Martinelli, M.C. Casale, M. Notaro, Nanostructured pure and Nb-doped Ti02 as thick film gas sensors for environmental monitoring , Sensors and Actuators B Chemical, 58, 310-317, (1999). 

L. Francioso, D.S. Presicce, P. SiciUano, A. Ficarella, Combustion conditions discrimination properties of Pt-doped Ti02 thin film oxygen sensor . Sensors and Actuators B Chemical, 123, 516-521, (2007). 

R.K. Sharma, M.C. Bhatnagar, G.L. Sharma, Mechanism of highly sensitive and fast response Cr doped Ti02 oxygen gas sensor . Sensors and Actuators B Chemical, 45, 209-215, (1997). 

J. Sheng, N. Yoshida, J. Karasawa, T. Fukami, Platinum doped titania film oxygen sensor integrated with temperature compensating thermistor . Sensors and Actuators B Chemical, 41, 131-136, (1997). 

FIGURE 1.13 Correlation between sensitivity (Rj/Rg, R, Rg the dc sensor resistance in a sample gas and air respectively) of (1.0 wt.%) Ag doped-WOj and SO2 concentration at 450°C. (Reprinted from Sens. Actuators B Chem., 77, Shimizu Y., Matsunaga N., Hyodo T., and Egashira M., Improvement of SO2 sensing properties of WO3 by noble metal loading, 35-40, 2001, with permission from Elsevier.)... 

FIGURE 1.14 COj sensitivity as a function of CO2 concentration for LajOj-doped Sn02 sensor. (Reprinted from Sens. Actuators B, 62, Kim D. H., Yoon J. Y., Park H. C., and Kim K. H., CO2 sensing characteristics of Sn02 thick film by coating lanthanum oxide, 61-66, 2000, with permission from Elsevier.)... 

Kobayashi T., Haruta M., Sano K., and Nakane N., A selective CO sensor using Ti-doped Fc203 with coprecipitated ultrafine particles of gold. Sens. Actuators B, 13, 339-349,1988. 

Sberveglieri G., Groppelli S., and Nelli P, Highly sensitive and selective NO and NOj sensor based on Cd-doped Sn02 thin films. Sens. Actuators B, 4, 445 50, 1991. 

Menesklou W., Schreiner H.-J., Hardtl K. H., and Ivers-Tiffee E., High temperature oxygen sensors based on doped SrTiOj, Sens. Actuators B, 59,184—189,1999. 

Sayago L, Gutierrez J., Ares L., Robla J. 1., HorriUo M. C., Getino J., and Agapito J., The interaction of different oxidizing agents on doped tin oxide, Sens. Actuators B, 25, 512-515, 1995. 

Cantalini C., Sun H. T., Faccio M., Ferri G., and Pehno M., Niobium-doped a-FcjOj semiconductor ceramic sensors for the measurement of nitric oxide gases. Sens. Actuators B, 24-25, 673-677, 1995. 

Zhou X. H., Sprensen O. T., and Xu Y. L., Defect structure and oxygen sensing properties of Mg-doped SrTiOj thick fi Im sensors. Sens. Actuators B, 41, 177-182, 1997. 

Torsi L., Pezzuto M., Siciliano P, Rella R., Sabbatini L., Valli L., and Zambonin P. G., Conducting polymer doped with metallic inclusions New materials for gas sensors. Sens. Actuators B, 48, 362-367, 1998. 

Chabukswar V. V., Pethkar S., and Athawale A. A., Acrylic acid doped polyaniline as an ammonia sensor,. Sens. Actuators B, 77, 657-663, 2001. 

Jain S., Chakane S., Samui A. B., Krishnamurthy V. N., and Bhoraskar S. V., Humidity sensing with weak acid-doped polyaniline and its composites. Sens. Actuators B, 96, 124-129, 2003. 

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