Abstract
By large-scale Monte Carlo simulations of semiflexible polymers in d=2 dimensions the applicability of the Kratky-Porod model is tested. This model is widely used as "standard model" for describing conformations and force vs. extension curves of stiff polymers. It is shown that semiflexible polymers in d=2 show a crossover from hard rods to self-avoiding walks, the intermediate Gaussian regime (implied by the Kratky-Porod model) is completely absent. Hence the latter can also describe force vs. extension curves only if the contour length is only a few times larger than the persistence length. Consequences for experiments on biopolymers at interfaces are briefly discussed.