implications in terms of fluctuation-induced forces has to our knowledge not been discussed.

In this Letter, we consider a polymer restricted, e.g. by plates or through absorption [@ErcoliniValleAdamcikWitzMetzlerRiosRocaDietler2007], to a planar geometry, modeled by a self-avoiding walk (SAW) of $N$ steps on a 2d lattice of spacing $a$. In the limit of large $N$ and small $a$ it is described by a continuum model. Start with a polymer with [*one endpoint fixed*]{}. Geometry $\cal A$ represented on the left of Fig. \[f:1\] is a half plane where the polymer’s end is fixed at the origin and free to wander to infinity. Then place a mesoscopic object, modeled by a disk of size $\ell$, at point $z=x+i y$. The object is impenetrable to the polymer, which is hence constrained to remain on the left of point $z$. We are interested in the free energy $$\begin{aligned}
{\cal F} = - k T \ln {\cal P}(z,\bar z) \ .\end{aligned}$$ ${\cal P}(z,\bar z) = Z(z,\bar z)/Z$ where $Z$ is the partition sum of the polymer in the absence of the object and $Z(z,\bar z)$ is the constrained one. Since the SAW in the continuum limit is conjectured to be described by SLE with parameter 