The interfacial tension at the CO2 + PEG interface for polyethylene glycols (PEGs) of molar masses Mw = 200 g/mol, Mw = 400 g/mol and Mw= 600 g/mol has been measured in the present work for the pressure range from 0.1 MPa up to 18.0 MPa at two different temperatures of 313 K and 333 K. An experimental technique was developed to study the interfacial interactions of the liquids in equilibrium with gas in a glass-windowed equilibrium cell by the means of the capillary rise method. The new technique allows determining interfacial tension and visualization of the interfacial interactions phenomenon in the two component system of polymer and compressed CO2. In the first step, the experiments were conducted for the measurement of the interfacial tension between CO2 and pure water in order to validate the experimental technique. The obtained results are in good agreement with the ones found in the literature. (C) 2015 Elsevier B.V. All rights reserved.