Nonionic surfactants, triblock copolymers (TBCs), were used to obtain and stabilize perfluorocarbon emulsions in a water solution (drop size, 200–300 nm). These TBCs differ in their molecular weight, length of polyethylene glycol (PEG) or polypropylene glycol (PPG) chains, and the ΣPEG/ΣPPG parameter value. Direct dependence is found between the amount of plasma proteins adsorbed on drops and the PEG/PPG value. The amount of the adsorbed proteins and their total mass per unit surface of the drop decreases as this ratio is reduced. Meanwhile, protein adsorption is almost independent of the molecular weight of TBCs and the length of PEG and PPG blocks. Adsorption of non-protein substance, chlorine e6, on emulsion drops increases with the rising ΣPEG/ΣPPG value and does not depend on other characteristics of TBC used as a stabilizer.