Surface viscosity aggregation number

Some essential discoveries concerning the organization of the adsorbed layer derive from the various spectroscopic measurements [38-46]. Here considerable experimental evidence is consistent with the postulate that ionic surfactants form localized aggregates on the solid surface. Microscopic properties like polarity and viscosity as well as aggregation number of such adsorbate microstructures for different regions in the adsorption isotherm of the sodium dedecyl sulfate/water/alumina system were determined by fluorescence decay (FDS) and electron spin resonance (ESR) spectroscopic methods. Two types of molecular probes incorporated in the solid-liquid interface under in situ equilibrium conditions... 

Among the possible additives that can increase medium viscosity with no apparent detrimental effects on the cells, dextran (up to 0.3%, w/v) has been found beneficial to these cultures. A limited number of experiments have shown that MCs and CMCs are not suitable protective agents because they cause microcarrier aggregation and flotation (i.e. collection on the liquid surface in the form of aggregates). 

An alternative mechanism might involve changes in micellar aggregation size and number at the isoelectric point caused by the adsorption of polymer at the micellar surface. With time, polymer micellar bridges could diminish as a result of stronger adsorption of polymers on the neutral (isoelectric point) surface and lead to lowering of the viscosity. Considerably more work is needed to understand these time-pH-dependent viscosity changes in amphoteric systems. 

Equation (2.17) allows us to make a number of conclusions. So, at the conditions mentioned previously, conservation increase, that is, initial nanoparticles aggregation intensification, results to nanocomposite melt viscosity reduction, whereas enhancement, i.e., increasing the nanoparticles degree of surface roughness, raises the melt viscosity. At = 2.0, i.e., the nanofiller particles have a smooth surface, the melt viscosity for the matrix polymer and the nanocomposite will be equal. It is interesting that the extrapolation of the MFl dependence, obtained experimentally, and for the one calculated using Eq. (2.19), values give the value of MFl = 0.602 g/10 min at d = 2.0, that is practically equal to the experimental value of MFI = 0.622 g/10 min. The indicated factors, critical ones for nanocomposites, are not taken into consideration in continuous treatment of melt viscosity for polymer composites (Eq. (2.8)). 

Alumina with neutral, basic and acidic (both Lewis type) surfaces was introduced into PE0ME-LiC104 electrolytes of various concentrations and examined with a variety of techniques. At higher salt concentrations when aggregation of ions occurs, fillers led not only to a decrease of the viscosity, but also to an increase in the fraction of free ions. The best results were obtained in the case of acidic fillers (Fig. 2.7). This results from interaction of acidic surface states with anions (Lewis bases) present in electrolyte as free ions, ion pairs, triplets, etc. The latter especially affect the viscosity and cation transference number. With the use of acidic filler, the fraction of free ions was increased as confirmed by Fuoss-Kraus calculations, as well as by Fourier transform infrared (FT-IR) investigations (Marcinek et al. 2005). The increase in the fraction of free ions means an increase of the number... 

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