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The creating of composite materials, possessing biological activity, arise during technological process – the substitution of air phase in porous film by liquid phase – solution of antigens, or other biologically active preparations, or theirs models – liquid medias with analogous properties.
For the present investigations were chosen thin (with thickness 0.10 – 0.15 mm) commercial polymeric flattened parallel porous membranes, based on nitrocellulose, with diameters of pores (D), as declared by manufactures, from 25 nm to 8 mkm.
The measurements of the topography of these filters have been conducted using easy Scan atomic force microscope (Nanosurf, Switzerland), working in the dynamic mode of intermittent contact under ambient conditions, and using scanning no contact white light interferometer microscope New View - 5022 (Zygo, USA).
Obtained images reveal the peculiar pore structure of these materials, obviously differing from the widespread presentation them, as the simple capillary assembly.
These results are proved to be useful in understanding our obtained values on integral time (T) of soaking similar drops (by volume about 1 mkl) of weakly diluted solutions albumin in distilled water on these membranes.
It turned up, that changing the nominal diameter of pores (D) from 25 nm to 550 nm lead to altering the values T to tenths and more times, while changing D from 550 nm to 8 mkm leave the values T practically constant and very low.
We suppose, that such facts are observed for the first time.
The abrupt changes in the values of T in said intervals of D were found also on the dependences T on such structural parameter characterizing membranes as “bubble point”, e.g. on the value of the minimal pressure displacing wetting water.
It is shown also, that the values of T are different for piling up the drops on the top side and bottom side of the filters with high degree of structural asymmetry.
The main equations, describing the observed phenomenon, are deduced.
These results have showed close relationship of the hydrodynamic peculiarities of flows in artificially created heterogeneous medium with the data on the surface pore structure of investigated materials.
The work was partly supported by the project RFFI 05 – 08 – 65530.
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