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The macromolecule properties determined by the pair density-density correlation function are considered. This function is calculated in the framework of mean field Lifshitz's theory. Using the correlation function, the hydrodynamic radius of a macromolecule is found in the Kirkwood approximation. The value of fluctuations in the macromolecule radius of gyration is calculated in the region of the globule-to-coil transition, which is connected with a sharp change in the fluctuational regime. The existence of a maximum of fluctuations in the transition region is shown

Quantitative theoretical results are compared with the available data of real experiments and computer simulations on single chain gyration and hydrodynamic radii and on binodal and spinodal curves of a polymer solution phase diagram. The comparison manifests a rather good agreement of the mean-field theory with experiments. However, the question of the observation of equilibrium polystyrene-cyclohexane single chain globules before solution precipitation remains to be discussed. Criterion of the globularity of an experimentally observed chain is discussed

The quantitative version of both Lifshitz-type and Flory-type theories are given, i.e. the intraglobular density distribution and, as a conclusion, the temperature (or solvent quality) dependence of the globule radius of gyration are calculated. Some delicate questions concerning the interrelation of these two types of theories are discussed.

Using Lifshitz's theory and interpolation Flory-type theory, density distributions and the interaction free energy for two globules equilibrated at an arbitrary distance ζ from each other are calculated; a special method was used for this calculation based on the introduction of two auxiliary uniform fields which do not perturn the globules' inner structures but fix the value of ζ. Then the corresponding pair virial coefficient and the coexistence binodal curve onthe T-c plane are calculated fin the second virial approximation. The spinodal T-c curve is also estimated