  Directed polymers (strings) and semiflexible polymers (filaments) are
one-dimensional objects governed by tension and bending energy, respectively.
They undergo unbinding transitions in the presence of a short-range attractive
potential. Using transfer matrix methods we establish a duality mapping for
filaments and strings between the restricted partition sums in the absence and
the presence of a short-range attraction. This allows us to obtain exact
results for the critical exponents related to the unbinding transition, the
transition point and transition order.
