X-ray Reflectometry of Thin Films Formed during Phase Separation of Organic Solutions of Aliphatic Polyethers in Water

The possibilities of X-ray reflectometry for studying the structure of planar liquid-phase membranes are demonstrated by the example of polyester films formed on the surface of deionized water from solutions of polylactoglycolide (PLG) in chloroform and tetraglycol (TG). It is found that the use of solutions with PLG concentrations ranging from 1 to 4 wt % or above 6 wt % leads to a proportional increase in the density of these films with preservation of their structure and thickness up to 25 Å. At a PLG concentration close to 5 wt % the PLG/TG system transits to an unstable state, characterized by intense penetration of PLG aliphatic chains into the water substrate bulk to a depth up to 100 Å.