  We perform equilibrium computer simulations of a two-dimensional pinned
flexible polymer exposed to a quenched disorder potential consisting of hard
disks. We are especially interested in the high-density regime of the disorder,
where subtle structures such as cavities and channels play a central role. We
apply an off-lattice growth algorithm proposed by Garel and Orland [J. Phys. A
23, L621 (1990)], where a distribution of polymers is constructed in parallel
by growing each of them monomer by monomer. In addition we use a multicanonical
Monte Carlo method in order to cross-check the results of the growth algorithm.
We measure the end-to-end distribution and the tangent-tangent correlations. We
also investigate the scaling behavior of the mean square end-to-end distance in
dependence of the monomer number. While the influence of the potential in the
low-density case is merely marginal, it dominates the configurational
properties of the polymer for high densities.
