Film formation behavior

Chemical solution deposition (CSD) procedures have been widely used for the production of both amorphous and crystalline thin films for more than 20 years.1 Both colloidal (particulate) and polymeric-based processes have been developed. Numerous advances have been demonstrated in understanding solution chemistry, film formation behavior, and for crystalline films, phase transformation mechanisms during thermal processing. Several excellent review articles regarding CSD have been published, and the reader is referred to Refs. 5-12 for additional information on the topic. Recently, modeling of phase transformation behavior for control of thin-film microstructure has also been considered, as manipulation of film orientation and microstructure for various applications has grown in interest.13-15... 

Most often in these processes, compounds such as acetic acid, acetylacetone (acac, 2,4-pentanedione), or amine compounds are employed, since these compounds readily react with alkoxides.4M877 A typical reaction involves the formation of new chemical species that (hopefully) possess physical and chemical characteristics that are more attractive in terms of solution stability and film formation behavior. An example reaction between a metal alkoxide and acetic acid is shown below ... 

Precursor structure and solution characteristics can have a significant impact on film formation behavior. In this section, film formation methods are first discussed, and then, in the subsequent section, the role of precursor structure on film formation and structural evolution into the desired crystalline state is... 

Yang, S.F. and Yang, S.H. (2002) Preparation and film formation behavior of the supramolecular complex of the endohedral metallofullerene Dy C82 with calix[8]arene. Langmuir, 18, 8488-8495. 

In 1993, Goh, et al. (77) used atomic force microscopy to study the film formation behavior of poly(butyl methacrylate) latexes. In the early stages of film formation, the surface latex particles have a protruding structure not unlike a basket of eggs. With time, the surface smoothes via lateral diffusion. 

Relative humidity can have a significant impact on drying behavior and film quahty. Water-based formulations that perform weU when apphed under dry conditions may be deficient under high humidity apphcation conditions. The rate of water evaporation is much slower at high humidity, but solvent evaporation continues. This results in solvent depletion during the critical phases of film formation and consequent poor film development. 

The oxidation products are almost insoluble and lead to the formation of protective films. They promote aeration cells if these products do not cover the metal surface uniformly. Ions of soluble salts play an important role in these cells. In the schematic diagram in Fig. 4-1 it is assumed that from the start the two corrosion partial reactions are taking place at two entirely separate locations. This process must quickly come to a complete standstill if soluble salts are absent, because otherwise the ions produced according to Eqs. (2-21) and (2-17) would form a local space charge. Corrosion in salt-free water is only possible if the two partial reactions are not spatially separated, but occur at the same place with equivalent current densities. The reaction products then react according to Eq. (4-2) and in the subsequent reactions (4-3a) and (4-3b) to form protective films. Similar behavior occurs in salt-free sandy soils. 

CV of solutions of lithium bis[ salicy-lato(2-)]borate in PC shows mainly the same oxidation behavior as with lithium bis[2,2 biphenyldiolato(2-)-0,0 ] borate, i.e., electrode (stainless steel or Au) passivation. The anodic oxidation limit is the highest of all borates investigated by us so far, namely 4.5 V versus Li. However, in contrast to lithium bis[2,2 -biphenyl-diolato(2-)-0,0 Jborate based solutions, lithium deposition and dissolution without previous protective film formation by oxidation of the anion is not possible, as the anion itself is probably reduced at potentials of 620-670 mV versus Li, where a... 

G Levy, JA Procknal. Unusual dissolution behavior due to film formation. J Pharm Sci 51 294, 1962. 

Photochemically induced phase transition is also found in the polyion complex films. Transient behavior of the cis isomer formation is more apparent in the complex films with polymer 6 and 7. 

The force-area curves for racemic and (5)-(+)-2-tetracosanyl acetate recorded with a barrier speed of 5 cm/min are shown in Figures 17 and 18, respectively. Again, both enantiomers showed identical monolayer behavior. The film balance behavior of the racemic acetate was indistinguishable from that of the pure enantiomers at temperatures above about 27°C however, below this temperature the force-area curves differed markedly even at low surface pressures, which indicates that racemic compound formation occurs at relatively large areas per molecule. 

Such behavior is similar in this respect to the electrochemical deposition of metal on a foreign substrate, in which an overpotential is required for nucleation, after which further growth of the metallic layer occurs at the characteristic redox potential of the metal, leading to a trace-crossing in the reverse sweep. However, recent voltammetric studies have shown that such trace-crossings still appear even if deposition processes or insoluble film formation cannot be detected... 

Amino-5-nitropyrimidine, cocrystallization, 455 Amorphous polymers, criteria for use in second harmonic generation, 250-251 Amphiphilic molecules polar Z-type Langmuir-Blodgett films, formation, 473-479 structures, transfer behavior, and contact angles, 474,476-477r Anharmonic oscillator models, nonlinear optical effect-microstructure relationship, 361... 

To explain the fact that HSPAN swells in water to form gel sheets or macroparticles rather than disintegrating into a gel dispersion, we initially felt that chemical bonding must take place between individual particles of water-swollen gel as water evaporates. Although we cannot totally eliminate this possibility, the proposal of primary chemical bonding is not necessary to explain the behavior of these films and conglomerates. For example, Voyutskii (19) has reviewed the formation of films from vulcanized rubber latexes and concludes that film formation in these systems is observed because of interdiffusion of ends of individual macromolecules in adjacent latex particles. This diffusion can take place even though individual latex particles are crosslinked, 3-dimensional networks and the continuity of the resulting films, even when... 

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