Monospher

Properties of Monospher 100 from Merck Amorphous, mean size 94 nm, particle size distribution available [1845]. 

Properties of Monospher 200 from Merck Spheres, 200 nm in diameter, BET specific surface area 20.5 m7g [1307]. 

Seidel A. et al.. The kinetics of dissolution of silica Monospher into water at different concentrations of background electrolyte. Solid State Ionics, 101/103, 713, 1997. 

The application of FFF techniques to assorted silica samples including colloidal microspheres (Ludox, Monospher, and Nyacol), fumed silica, and chromatographic silica (see Table II) are discussed in this section. In several cases, different FFF systems are applied to the same samples, and the results are compared. The acquisition of size distribution data is emphasized, but the possibilities for measuring densities and porosities for spherical particles and structural factors for nonspherical silica are also discussed (and in one case demonstrated). 

Monospher Colloidal Silica. Superimposed thermal FFF fracto-grams (system Therm I) of various sizes of Monospher colloidal silicas (E. Merck) run in acetonitrile are shown in Figure 7. A AT of 53 K (cold wall temperature of 290 K) was used to obtain these data. The broadness and excessive tailing of the peaks suggests a high polydispersity for the particle populations. In addition, the proximity of elution of the Monospher 100 and 150 samples indicates that their mean sizes are not as different as... 

Figure 7. Fractograms of four different Monospher silicas suspended in acetonitrile by thermal FFF (system Therm I).

FIGURE 41.8 Separation of Monospher colloidal silicas with power-programmed sedimentation FFF (Sed II system). 

FIGURE 41.9 Sedimentation FFF (Sed II system) fractogram and electron micrographs of Monospher 250 aggregates. 

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