Particles polymolecular

There are various methods for the determination of the surface area of solids based on the adsorption of a mono-, or polymolecular layer on the surface of the solid. These methods do not measure the particle diameter or projected area as such, but measure the available surface per gram or milliliter of powder. The surface measured is usually greater than that determined by permeability methods as the latter are effectively concerned with the fluid taking the path of least resistance thru the bed, whereas the adsorbate will penetrate thru the whole of the bed as well as pores in the powder particles. These methods appear to be more accurate than surface areas calculated from weight averages or number averages of particle size because cracks, pores, and capillaries of the particles are included and are independent of particle shape and size... 

State of subdivision, implying that the molecules or polymolecular particles dispersed in a medium have at least in one direction a dimension roughly between 1 nm and 1 pm, or that in a system discontinuities are found at distances of that order. (Gold Book online, 1972 entry [2].)... 

Karnaukhov, A. Kiselev, and co-workers (12,14,135-142) investigated the hypothetical geometrical structure describes by a corpuscular model in the form of a system of particles (globules) of uniform size in contact with one another. The diameter of the particles and the number of contacts between particles were taken as the main parameters of the model. An approximate theory of polymolecular adsorption and capillary condensation was developed. The simultaneous process of polymolecular adsorption and capillary condensation was analyzed for porous systems with a globular structure. It was shown that the contribution of both processes determines the form of the adsorption isotherm. The theoretical results obtained were compared with experimental data for different silica adsorbents by using different methods. 

The general concept of these sols as two phase systems, in which the dispersed phase consists of polymolecular particles stabilised by a surface charge (" capillary electric charge ) at the phase boundary, proved useful. 

Though the polymolecularity of such molecular associations perhaps might remind one phenomenologically of the particles of hydrophobic sols, from the thermo-... 

---