  A cubic structure of polymer colloid complexes is studied. The technique of
the research includes i) an analysis of well-known literature SAXS data; on
this base, at some assumptions, ii) constructing a simple model to estimate
geometric structure parameters and to receive a simulated scattering curve,
iii) calculations of energetic parameters by help of the analytical fluctuation
theory of the phase transitions; iv) comparing the model with the real
structure obtained from the SAXS data by the electron density distribution
reconstruction method. In the presence of an effective field the 2-nd order
phase transition transforms to the 1-st order one in the vicinity of the
Lifshitz point. As a result, a bicontinuous structure in cubic mesophases is
formed.
