The thermodynamics of mixing at infinite dilution of a series of 25 low molecular weight aprotic solutes covering a broad range of polarity from n-alkanes to dimethylsulphoxide with molten linear polyethylene has been investigated by gas-liquid chromatography between 135 and 175°C. The lack of any specific solute-polymer interactions load to partial molar free energies and enthalpies of mixing at infinite dilution, ΔG ∞ 1 and ΔH ∞ 1 , are always positive. Quantitative analysis of the ΔG ∞ 1 and ΔH ∞ 1 variations with probe structure may be performed according to an empirical linear correlation ΔG ∞ 1 or ΔH ∞ 1= f(μ 2 1 ), which acknowledges the influence of solute polarity through its dipole moment μ 1 ( ΔH ∞ 1=( KJ mol −1)=1.43+0.48 (μ 1 × 10 30) 2 , R(25)=0.95 for instance). Alternatively, the Hildebrand-Scatchard equation, which acknowledges the influence of solute cohesion through its solubility parameter δ 1 ( ΔG ∞ 1N 1 or ΔH ∞ 1 V 1 =(δ 1−δ 2) 2 , R(25)=0.90) and which makes it possible to derive a reliable value of the PE solubility parameter: β 2=11.3 (J cm −3) 0.5 at 140°C for instance. These two apparently different and successful approaches may probably rest on similar physical grounds because dipolar interactions are the major factor of solute cohesion for the population under investigation.