  Using Brownian Dynamics, we study the dynamical behavior of a polymer grafted
onto an adhesive surface close to the mechanically induced
adsorption-stretching transition. Even though the transition is first order,
(in the infinite chain length limit, the stretching degree of the chain jumps
discontinuously), the characteristic relaxation time is found to grow according
to a power law as the transition point is approached. We present a dynamic
effective interface model which reproduces these observations and provides an
excellent quantitaive description of the simulations data. The generic nature
of the theoretical model suggests that the unconventional mixing of features
that are characteristic for first-order transitions (a jump in an order
parameter) and features that are characteristic of critical points (anomalous
slowdown) may be a common phenomenon in force-driven phase transitions of
macromolecules.
