[Estimation of the width of the transition zone from bilayer to solid phase]

A transition region from black bimolecular lipid film to the volume phase of a lipid solution (to tore) has been studied by the model which links the profile and size of the transition region with disjoining pressure brought about by the Van der Vaals's forces. Simple formulas linking the profile and size of the transition region with the thickness and wetting angle of the bilayer lipid membrane have been obtained. If the terminus of the transition zone is determined by the cross section where the real thickness of the film is one per cent more than that obtained by extrapolation of the tore surface profile outside the transition zone into this zone, the width of the transition region from the bilayer to the volume phase is essentially less than 1 mkm. With the decrease of the bilayer thickness the width of the transition zone also decreases.