  We report studies of the equilibrium and the dynamics of a general set of
lattice models which capture the essence of the force-induced or mechanical DNA
unzipping transition. Besides yielding the whole equilibrium phase diagram in
the force vs temperature plane, which reveals the presence of an interesting
re-entrant unzipping transition for low T, these models enable us to
characterize the dynamics of the process starting from a non-equilibrium
initial condition. The thermal melting of the DNA strands displays a model
dependent time evolution. On the contrary, our results suggest that the
dynamical mechanism for the unzipping by force is very robust and the scaling
behaviour does not depend on the details of the description we adopt.
