Polymer electrolytes explanation

The interfacial phenomena in solid LiX/PE systems were extensively studied by Scrosati et al For the dry PEO-based polymer electrolytes it was shown that the interfacial stability can be significantly enhanced by decreasing the ceramic particle size to the scale of nanometers. The mechanism of the processes leading to improved stability is not well understood and some explanations include scavenging effects and screening of the electrode with the ceramic phase. "... 

Our explanation implies that the excess polymer precipitates onto the surface of the particles when the polymer concentration becomes larger than its solubility, which decreases with increasing electrolyte concentration in the solution. 

Detailed electrochemical studies on model oligoferrocenylsUanes that possess two to nine ferrocene units fully support this explanation [102]. The peak separations for the different polymers, which provide a usefid estimate of the degree of interaction between the metal centers, are generally in the range A i/2=0.20-0.25 V in CH2CI2 with [Bu4N][PFg] as supporting electrolyte, with some depen-... 

In nanoscale catalyst particles the ratio of the different crystallographic faces are depending on the particle size thus giving an explanation for the particle size effects observed in electrolytes containing adsorbing anions. Since the perfluorinated polymer sulfonic acids are not adsorbing to the platinum sxuface, particle size effects are not so prominent in PEFC. 

Optical properties of electroactive polymers as measured ellipsometrically depend greatly on conditions used to grow the film. Greef et al. point out significant optical differences between reduced PA films grown on different materials (for PA, on Pt, n = 1.55-1.58, whereas on Au, n could attain values as high as to 1.7). Explanations in terms of the presence of larger amounts of solvents within reduced films with lower n values (n for aqueous electrolytes is typically ca. 1.34) are not valid. Just as a very low value of n can be traced to a Lorentzian oscillator at... 

Explanation for the existence of order in these dilute dispersions of isotropic spheres requires the existence of forces whose range is long compared to those of chemical valence bonds or van der Waals forces. The polymer spheres possess bo md sulfate radicals on their surfaces, which can dissociate even in media of moderate polarity. The resulting coulombic forces, even when partially shielded by an atmosphere of free coimterions, possess the required long range. This range is drastically shortened, however, when neutral electrolyte is added, thereby producing an order-disorder transition. 

The effect of electrolyte addition on the hydrophobic microdomain has also been investigated. Addition of NaCl to the polymer solution of RAM causes a 12 nm blue shift in 2(max) while the change for HR AM is negligible and within the error limit. The explanation advanced is that salt addition is causing a reduction in hydrodynamic volume of the polymer. This squeezes the probe from the core and pushes it toward the interface which is more hydrophilic. Interestingly, the Idata obtained from using pyrene as an emission probe generates the same information. 

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