Determination of Phenomenological Diffusivities from Numerical and Experimental Data

4 Determination of Phenomenological Diffusivities from Numerical and Experimental Data 

In order to determine the remaining four phenomenological diffusivity parameters, four types of measurements were performed. One is the interdomain distance 

Based on Saxena s efforts (Saxena, 2001) and the adjustment on the timescales of phase separation to make numerical simulation data coincide with hght scattCT-ing results, the following phenomenological diffusion coefficients for the ternary PMAA/MAA/water (7 wt%/3 wt%/90 wt%) system at 80°C were obtained  

Predictions of these dimensionless parameters result in the following frequency spectra (Fig. 1.4.39) and composition profiles (Fig. 1.4.40). 

Frequency spectra in Fig. 1.4.39 can be seen to be qualitatively the same as those of qt3 and qt4, and almost the same as that of qt6 (Table 1.4.2). This is expected since values of Py are all the same. However, composition profiles in Fig. 1.4.40 are more qualitatively the same as those of qtl, qt2, qt5, and qt7 due to the combination of phenomenological diffusion coefficients obtained from experimental data. They indicate higher concentrations of MAA in the polymer-rich phase domains, which should result in more polymerization reaction and enhanced coarsening from those domains in the corresponding reactive system. 

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