Salt, concentration dopant

A comprehensive screening study to identify optimal release thermodynamics should include both mixed metal amine salts as well as low concentration dopants. It is, however, not practically possible due to the large number of possible combinations. Limiting the potential elements to 3d and 4d transition metals, alkali, alkaline earth metals, and halides down to the sixth period of the periodic table, the number of candidate structures with just two different cations and two different anions in a super cell of 8 formula units is almost 2 million. An intelligent screening method is therefore needed to cut down the number of calculations e.g., a genetic algorithm. 

Figure 5 Magnetic susceptibility versus concentration of added salt solution at a fixed polymer concentration, c = O.Icq, and fixed dopant level, y = 2%, in chloroform. A 0.1 M salt concentration is equivalent to a volume fraction of 2 10 3 on the abcissa. (From reference 25).

In case of crystals of Cu-Dy composite formed under sonication, the concentration of dysprosium increased while in case of the crystals of Mn-Dy and Co-Dy composites, the concentration of dopant, Dy, decreased indicating a strong attraction of Dy for Cu compared to its weak interaction for Mn and Co ions. Nevertheless, the possibility of some of the Dy having been ejected out due to forceful cavitational effect of the ultrasound from the lattice of Mn and Co cannot be ruled out. Higher percentage of Cu, Mn, and Ce in case of Cu-Ce, Co-Ce and Mn-Ce composites, synthesized under sonication compared to normal crystals, could be attributed to the change in the composition of the lattice pattern due to the mechanical impact of ultrasound, whereas, such an effect has not been found in Co salts. These can be seen in Table 11.1. 

Influence of polymerization conditions upon incorporation of flavin-containing polyanion. The amount of polyanion (1) incorporated as dopant in a PPy film during electropolymerization can easily be controlled by changing the ionic strength (low molar mass salt) and/or the pH of the monomer solution. The correlation between the amount of polymer-bound flavin incorporated in the film and the concentration of the added low molar mass salt, sodium-p-toluenesulphonate (NaOTs), at pH=7 is shown... 

X-ray photoelectron spectroscopy ( XPS ) reveals that impregnation of Raney catalysts with basic-pH salts, e.g. ammine complex types containing Pd or Pt, rather than previously reported acid salts, modifies the placement of PM within the Ni catalyst s sponge stmcture. The PM placement is expressed as a surfaceAiulk ( S/B ) ratio for the normalized dopant concentration. The resulting basic salt catalysts have lower S/B ratios and also generally perform better in activity and life tests than the acidic salt types. 

For example, a solid polymer electrolyte is a solution of a lithium salt in a PEO matrix the ionic conductivity of such material is due to the mobility of lithium cations and their anions in an electric field. The objective of the electrolyte system is to provide mechanical integrity and ion-conducting properties. PEO is a semicrystalline polymer at room temperature and has an exceptional property to dissolve with high concentration of a wide variety of dopants. 

The electrolyte concentration employed during synthesis also influences the conductivity of polypyrrole. This has been observed for polypyrrole films electrogenerated on aluminum electrodes, where the conductivity varies from 100 to 320 S cm when the electrolyte concentration (/-butylammonium p-toluenesulfonate salt) increases from 0.05 to 0.3 M [37]. Similar results have been obtained by Satoh et al. [51] using ITO glass electrodes. These higher conductivities should be associated with the higher dopant concentration or the influence of the electrolyte concentration on the polymerization rate. 

As already mentioned in the Introduction, pioneering work on solid PEC dates back to the 1960s, when Michaels and coworkers published systematic studies on the frequency dependence of the complex permittivity [2, 3]. They investigated the influence of the RH and the concentration of dopant salt like NaBr, respectively, on the complex permittivity of PEC. The complexes were made of poly (vinyl benzyl trimethyl ammonium chloride) (PVBTAC) and sodium poly(styrene sulfonate) (NaPSS). 

The threshold value for electrical conductivity is shown to be sensitive to the morphological structure of the salt network. Measurable electrical conductivity of these blends shows very low values at approximately 0.5 % by volume of the salt. At this threshold value for electrical conductivity, a fi tal network is established through the nylon host. Lower onsets of electrical conduction in the PANI-0.5-HMSA / nylon 6, PANI-0.5-HDBSA / nylon 12 and PANI-0.5-HCSA / nylon 6 blends paralleled a finer, more branched network whereas the lower conductivities accompanied a coarser, more globular morphology in the PANI-0.5-HMSA/ nylon 12, PANI-0.5-HDBSA / nylon 6 blends. At concentrations less than 5 % (vol/vol) a conducting network forms throughout the nylon sample. As salt level increases above the threshold value, the network be mes dense and convoluted and the electrical conductivity becomes less sensitive to dopant anion functionality. 

In a former investigation, an inversion of the helix sense with dopant concentration has been observed which is unusual. The phenomenon was explained again by a change of the cisitrans ratio of the surfactant (the chloride of the decyl ester of L-proline). NMR gave at least qualitative evidence for the existence of the two rotamers [28]. An inversion of the twist sense has been found with a-hydroxy carbon acids and some corresponding potassium salts [23]. For all of the investigated couples the respective opposite handedness was proven by a twist compensation seen in contact preparations. The result is unexpected because the molecular chirality of the acid and the salt are nearly identical. It was supposed that the presumably different locations with respect to the micelles due to the ionic character of the salt and/or a dimerization of the acid could be the reason for the observed behavior. 

Yttrium silicate cerium phosphors of superior properties were synthesized by Marsh et al. (2002). A precipitate was obtained by adding excess ammonia to a sol obtained from a mixture of tetraethyl orthosilicate (TEOS) in ethanol and yttrium nitrate in concentrated HNO3 solution. The precipitate was stirred in 2-propanol with cerium nitrate as the precursor for the dopant (see above for syntheses with dopant salt addition), dried and fired at 1600°C/2 h. Apparently the particles were not monodisperse (as in the ammonia-mediated synthesis in the so-called StOber method see Gel Microspheres Precipitated through pH Control ). 

N. Satyanarayana, G. Govindaraj, A. Karthikeyan, Effects of differing ratios of network modifier (Ag20) to network formers (M0O3 + V2O5) and dopant salt (Agl) concentrations in silver-based superionic glassy compounds. J. Non-Cryst. Solids 136(3), 219-226 (1991)... 

CP are sensitive to a wide range of synfliesis parameter, such as deposition potential and current density, the type and concentration of dopant, and stimulation salts, polymerization temperature, solvent, monomer concentration, electrode, and pH (Maw et al. 2005). CPs diat have been deposited under different synfliesis conditions can be considered to be distinctly different materials, albeit within a family. 

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