The water sorption of the films of polyacrylic acid, guar gum and PAA-guar mixtures of different compositions, prepared at 25°C and 70°C, was studied. The chemical potentials of water ∆μ1, polymer component ∆μ2, the average Gibbs energy of interaction of polymers and mixtures with water ∆gm, the average Gibbs mixing energy of PAA and guar ∆gx have been determined. It is established that the increase in the preparation temperature significantly enhances the films’ sorption capacity in relation to water. It is determined that the Gibbs mixing energy of polyacrylic acid with guar is negative for all component ratios (∆gx < 0). The second derivative of Gibbs energy has different signs, and in a wide range of concentrations of the mixture it is negative. This indicates the absence of compatibility and the formation of two-phase colloidal systems in mixtures of guar with PAA. The increase in the preparation temperature of mixtures leads to an increase in the interaction of the components in the two-phase system, which may be related to the reduction in size of the associates of macromolecules of guar in aqueous solutions.