  The conformational behavior of a polymer in a critical binary solvent
confined in a porous medium is studied. The size of the polymer in bulk, which
is mainly governed by the correlation length of the solvent density
fluctuations, depends on the proximity to the critical point of the binary
mixture. We find that in contrast to the bulk behavior, the conformational
properties of the polymer in a porous medium depends strongly on the pore size.
The latter controls the correlation length of the solvent density fluctuations
and thus determines the polymer size.
