To calculate the adsorption (Г_i) of liquid-crystalline nanodemulsifiers on the basis of poly(ethylene oxide)–poly(propylene oxide) block copolymers on the liquid-gas interface, the Frumkin equation:  Г_i=Г_m[1–exp(Ds_i/RTГ_m)] was used. Correlation equations are proposed for calculating the minimum surface tension of block copolymers at maximum adsorption  (Г_m) depending on the molecular mas and the degree of hydroxyethylation of the corresponding oligomers, and a general adsorption isotherm in the coordinates  Г_i–(–Δs) is constructed and some comments, interpretations and conclusions based on the results of the research are presented.