  Taking into account the well known correspondence between the field
theoretical O(n)-vector model in the limit $n\to 0$ and the behavior of
long-flexible polymer chains in a good solvent the investigation of ideal
polymer chains adsorption onto structured surface like as a chemical step
(where one part of a surface is repulsive for polymers and other part is at the
adsorption threshold) was performed. The two-point correlation function of
ideal polymer chain in the half - space bounded by structured surface with
different adsorption energies $c_{1}$ and $c_{2}$ (with $c_{1}\neq c_{2}$) and
the "closest form" for the free propagator of the model were obtained in
analytical form. Besides, the force which ideal polymer chain with free end
exerts on the structured surface, when the other end is fixed at the surface,
was calculated. The obtained results indicate that the process of homopolymer
adsorption onto structured surfaces should be described by different scaling
laws than universal scaling laws predicted in the literature for homopolymer
adsorption on homogeneous surfaces.
