Microbalance studies

As repeatedly stressed, the doping processes imply the diffusion of electrolyte counterions to compensate for the electric charge assumed by the polymeric chain and thus polymers are expected to experience changes of mass upon doping. Consequently, by monitoring these changes it is possible to control the nature and the extent of the doping processes. 

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For isothermal measurements, it is advisable to use a furnace of low thermal capacity unless suitable arrangements can be made to transport the sample into a preheated zone. The Curie point method [132] of temperature calibration is ideally suited for microbalance studies with a small furnace. A unijunction transistor relaxation oscillator, with a thermistor as the resistive part with completion of the circuit through the balance suspension, has been suggested for temperature measurements within the limited range 298—433 K [133]. 

Bohannan, E. W., Huang, L. Y Miller, F. S., Shumsky, M. G. and Switzer, J. A. (1999) In situ electrochemical quartz crystal microbalance study of potential oscillations during the electrodeposition of CU/CU2O layered nanostructures. Langmuir, 15, 813—818. 

F. Caruso, E. Rodda, D.F. Furlong, K. Niikura, and Y. Okahata, Quartz crystal microbalance study of DNA immobilization and hybridization for nucleic acid sensor development. Anal. Chem. 69, 2043-2049 (1997). 

Y. Sato and F. Mizutani, Electrochemical responses of cytochrome c on gold electrodes modified with nucleic acid base derivatives - electrochemical and quartz crystal microbalance studies. Electrochim. Acta 45, 2869-2875 (2000). 

Kemell, M. Saloniemi, H. Ritala, M. Leskela, M. 2001. Electrochemical quartz crystal microbalance study of the electrodeposition mechanisms of CuInSe2 thin films. /. Electrochem. Soc. 148 010-018. 

Electrochemical quartz crystal microbalance studies at Sn-modified Pt and Au electrodes allowed a further insight into the kinetics and mechanism of the reduction process [58, 59]. The problems connected with the chemisorption of N03 ions were discussed in [30, 60]. 

A quartz crystal microbalance study of the kinetics of CdSe deposition from the preceding solution (nitrilotriacetate) showed an importance difference in the mode of growth of the CdSe below and above Rc [42]. Below Rc (hydroxide mechanism), a periodicity in the deposition rate was observed, with a period corresponding to a film thickness of ca. 5 nm—i.e., the approximate size of a single... 

Film electrodes have been essential components of quartz microbalance studies of stoichiometry of many electrodeposition and dissolution experiments as well as polymer electrode characterization [25]. In the quartz microbalance, changes in mass are detected by measurement of changes in the resonant frequency of a quartz crystal oscillator as the mass adhering to the surface changes. The oscillation is feasible because thin-film metal electrodes (typically gold) applied to opposing faces of a piezoelectric quartz crystal serve both to induce the oscillation and to provide a site for electrochemical reaction. 

Microbalance studies can be extended to finely divided catalysts if a device is provided for suspending the powders on the hang-down wire. Boats and other containers are undesirable since they contribute excessively to the total load on the system. In many cases fine powders can be compressed at reasonable pressures into compact masses to permit their suspension without a container (Gulbransen, 77). Little information is available now as to applications of this technique, and hence discussion will be focused on the three other classes, although powders can be studied when contained in lightweight boats of platinum or quartz. 

Matsuura K, Tsuchida A, Okahata Y, Akaike T, Kobayashi K (1998) A quartz-crystal microbalance study of adsorption behaviors of artificial glycoconjugate polymers onto chemically modified gold surfaces and their interactions with lectins. Bull Chem Soc Jpn 71 2973-2977... 

Zhang GZ, Wu C (2009) Quartz crystal microbalance studies on conformational change of polymer chains at interface. Macromol Rapid Commun 30 328-335... 

The luminescence of a thin film coated with [Re(CO)3(/u.-4,4 -bipyridine)Cl]4 was quenched by nitrobenzene vapor because of electron transfer. Recently, mesoporous thin films of [Re(CO)3(/u.-L)Cl]4 (L = 4,4 -pyrazine or 4,4 -bipyridine) have been utilized as sensors for volatile organic compounds (VOCs). The host-guest interaction between the rhenium cyclophanes and VOCs was confirmed by quartz crystal microbalance studies. 

Copper.—The oxidation of copper and adsorption of oxygen on copper surfaces has been examined by a variety of techniques. Recent work utilizes LEED, XPS," UPS, ELS, ° and electron microscopyas well as microbalance studies.Unlike similar studies carried out on silver and gold this... 

Barisci, J.N., Wallace. G.G., and Baughman, R.H. 2000b. Electrochemical quartz crystal microbalance studies of single-wall carbon nanotubes in aqueous and non-aqueous solutions. Electrochimica Acta 46, 509-517. 

Salgado,L., Tejo, G., Meas, Y., and Zayas, T. 2006. Cyclic voltammetry and electrochemical quartz crystal microbalance studies of a rhodized platinum electrode in sulfuric acid solution. Journal of Solid State Electrochemistry 10, 230-235. 

Uchida, H., Ikeda, N., and Watanabe, M. 1997. Electrochemical quartz crystal microbalance study of copper adatoms on gold electrodes Part II. Further discussion on the specific adsorption of anions from solutions of perchloric and sulfuric acid. Journal of Electroanalytical Chemistry 424, 5-12. 

Methods include TPSR/HRV - variation of heating rate with TPSR TPSR-IR - initial rates with TPSR GA - microbalance studies TEM - movement of Ni particles on a carbon substrate during TEM studies. 

Schierbaum K. D., Zhou R., Knecht S., Dieing R., Hanack M., and Gdpel W., The interaction of transition metal phthalocyanines with organic molecules A quartz-microbalance study, Sens. Actuators B, 24, 69-71, 1995. 

Quartz crystal microbalance studies have shown that the movement of the solvent molecules associated with ions can be considerable. Using PPy prepared in sodium dodecyl sulfate, a mix of both cation- and anion-driven processes was seen when cycled in NaCl, and the mass changes involved indicated that four water molecules moved per Cl and 15 water molecules per Na" " [11]. The role of solvent water molecules has also been examined for PPy in dodecyl benzene sulfonate (DBS), a very widely studied system, where the insertion of cations accounted for only 20% of the mass change upon polymer reduction, indicating that four water molecules were brought into the film with each Na+ [12]. As the electrolyte concentration was changed from 0.1 M to 6 M, the total inserted mass became smaller and the mechanism moved from pure cation transport to an equal amount of anion transport [13]. These results were said to support an osmotic expansion model, whereby the difference in osmotic pressure between the electrolyte and polymer bulk (greater with more dilute electrolyte solutions) drives solvent movement. 

Electrochemical Quartz Crystal Microbalance Studies of the Growth of Perylene-Containing Films... 

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