Their results show that dispersion (apolar, Van der Waals) forces are the main portion of the enthalpy. These forces provide around 60% of Gibbs free energy for DNA denatu- and ∆H p =22% i.e. the main portion (57%) of the enthalpy of the DNA thermal denaturation process belongs to dispersion forces that correspond to the conclusion of authors. However, calculating the cohesive parameters of the polyelectrolyte as an average from four DNA bases is unclear because it did not consider the role of phosphate and other polar groups in a polyelectrolyte.