order. However, in most experiments, the tethering of the polymer to
the AFM tip is by nonspecific adsorption; as a result, the polymers
being stretched between the tip and the substrate have various
-lengths\citep{1li00}. In addition, the interactions between the tip
+lengths\citep{li00}. In addition, the interactions between the tip
and the surface often cause irregular features in the beginning of the
force curve (\cref{fig:expt-sawtooth}), making the identification of
the first peak uncertain\citep{carrion-vazquez00}. Furthermore, it is