Quartz crystal microbalance measurements

Fig. 5 Quartz crystal microbalance measurements during potentiodynamic polymerization of 4,4 -dimethoxy-bithiophene in CH2CI2, 0.1 M TBAPFe,...

As with all supramolecular structures, one of the most important issues is whether a direct relationship between the structure of a material and its function or properties can be established. In the following, some examples of polymer systems which show such a correlation will be discussed. The materials addressed will include block copolymers, polyalkylthiophenes and a multilayer system based on the self-assembly of polyelectrolytes. Detailed studies on the electrochemical properties of redox-active polymers, based on poly(vinyl pyridine) modified with pendent osmium polypyridyl moieties, have shown that electrochemical, neutron reflectivity and electrochemical quartz crystal microbalance measurements can yield detailed information about the structural aspects of thin layers of these materials. 

Y. Ebara, H. Ebato, K. Ariga, Y. Okahata, Interactions of Calciinn Ions with Phospholipid Membranes. Studies on jr-A Isotherms and Electrochemical and Quartz-Crystal Microbalance Measurements , Langmuir, 10, 2267 (1994)... 

The photoswitchable complexation/dissociation properties of n donor-acceptor complexes between xanthene dyes and photoisomerizable bipyrid-inium salts have been used to generate an optoelectronic interface [97] (Fig. 28). Eosin isothiocyanate (52) was covalently linked to an electrode surface via a thiourea bond (Fig. 28A). The electron acceptor 3, 3 -bis(N-methylpyridinium) azobenzene 53 was used as the photoisomerizable component. The association constants of the n donor-acceptor complexes generated between eosin and 53a or 53b in solution correspond to Ka — 8.3 x 103 M-1 and Ka — 3.4 x 103 M 1, respectively. The analysis of complexation on the functionalized surface was accomplished by quartz crystal microbalance measurements. The frequency change (Af) of a piezoelectric quartz crystal on which a mass change Am occurs is given by the Sauerbrey equation (Eqn. 1) ... 

In addition to deriving the equation that now bears his name, Sauerbrey also developed a method for measuring the characteristic frequency and its changes by using the crystal as the frequency-determining component of an oscillator circuit. It should be mentioned that the Sauerbrey equation was developed for oscillation in air and only applies to rigid masses attached to the crystal. However, Kanazawa and Gordon have shown that quartz crystal microbalance measurements can be performed in liquid, in which case a viscosity-related decrease in the resonant frequency is observed ... 

The author thanks M.L. Van Kavelaar and M.j, van Kavelaar for the microscopic studiesr M.D. Ward for the four-point probe conductivity determinations and quartz crystal microbalance measurements, and L.E. Firment and C.L. Davis for XFS studies. 

M. Dobashi, S. Yoshihara, T. Shirakashi and T. Yokota, Influence of Additives in Electrolytic Solution on Mass Change of Zinc Electrodeposited Films - Investigation by Quartz Crystal Microbalance Measurement, The Journal of the Surface Finishing Society of Japan. Vol. 48, 1997, 330-336. 

Quartz-crystal microbalance measurements showed that the total amount of adsorbed polymer appeared unaffected by the presence of glycerol. The kinetics of adsorption of PLL-g-PEG from the HEPES-glycerol solution to the interface was investigated to help understand the effect of the increased viscosity on the rehealing of the tribo-stressed... 

Friedt JM, Choi KH, Francis L, Campitelli A (2002) Simultaneous atomic force microscope and quartz crystal microbalance measurements interactions and displacement field of a quartz crystal microbalance. Jpn J Appl Phys 1 41(6A) 3974-3977... 

Time resolved in situ liquid atomic force microscopy and simultaneous acoustic impedance electrochemical quartz crystal microbalance measurements a study of Zn deposition. Anal Chem 81(20) 8466-8471... 

Figure 4.25. Oscillatory phenomena dining galvanostatic oxidation of HCOOH on Pt at 0.15 mA cm in 0.9 M HCOOH - 0.5 M H2SO4 [136]. a) Pt electrode mass (indicated as fiequency change Af in quartz crystal microbalance measurements), b) Pt surface energy Af and c) electrode potential (With kind permission from Springer Science+Business Media Journal of Solid State Electrochemistry, Simultaneous oscillations of surface energy, superficial mass and electrode potential in the course of galvanostatic oxidation of formic acid, 9,2005, 347-53, Lang GG, Seo M, Heusler KE, figure 4.)...

The author would like to thank Thomas Springer (Los Alamos) for many contributions to the mathematical modelling aspects mentioned here, Ruth Sherman (Los Alamos) who gathered much experimental data on RuOj, Judith Rishpon (University of Tel Aviv) who made the quartz crystal microbalance measurements of Fig. 14, and Bernard Boukamp (University of Twente) who has allowed the author to use his non-linear least-squared error fitting routines for impedance data analysis. 

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