Silica sphere diameter distribution

Figure 1.19 (a) Sphere diameter distribution for silica particles precipitated using R5 peptide (black) and R5-EAK (white) (b) Sphere size distribution for silica particles formed with RS-EAKi at different temperatures. Reprinted with permission from Ref [67] 2008, American Chemical Society. 

At pH 5.2, hollow spheres are formed with a uniform size distribution and an average diameter of approximately 1 fj,m. These silica spheres are thermally very stable and hollow (Fig. 9.17), possessing a relatively thin shell with a very regular thickness of 80-130 nm composed of 7-8 nm thick layers of silica with an interlamellar spacing of 3-4 nml l. ... 

Chromatographic Silica. Silica particles used for liquid chromatographic supports are generally porous spheres in the diameter range 2-20 pm. Important properties of these particles bearing on chromatographic performance include mean size, size distribution, presence of aggregates and fines, and particle porosity. All these characteristics should be accessible to measurement by FFF most are described later. 

The size distributions of colloidal suspensions of nanoparticles 74 nm to 14 nm in diameter are analyzed on-line. The sols are first diluted in water seeded with enough TFA to attain electrical conductivities in the range of 0.01 S/m. The solution is then finely dispersed into an atmosphere of CO2 via a Taylor cone-jet. The resisting electrospray of ultrafine droplets dries, transferring the solution particles virtually uncontaminated into the gas. There they are sized by means of a differential mobility analyzer and an inertial impactor of unusually high resolution. The technique is first tested successfully with previously calibrated monodisperse polystyrene latex (PSL) spheres 74 to 21 nm in diameter. It is then used to size a solution of colloidal silica with particle diameters nominally between 10 and 14 nm. 

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