  The polymer systems are discussed in the framework of the Landau-Ginzburg
model. The model is derived from the mesoscopic Edwards hamiltonian via the
conditional partition function. We discuss flexible, semiflexible and rigid
polymers. The following systems are studied: polymer blends, flexible diblock
and multi-block copolymer melts, random copolymer melts, ring polymers,
rigid-flexible diblock copolymer melts, mixtures of copolymers and homopolymers
and mixtures of liquid crystalline polymers. Three methods are used to study
the systems: mean-field model, self consistent one-loop approximation and self
consistent field theory. The following problems are studied and discussed: the
phase diagrams, scattering intensities and correlation functions, single chain
statistics and behavior of single chain close to critical points, fluctuations
induced shift of phase boundaries. We concentrate on static, equilibrium
properties of the polymer systems.
