  We study the conformation and dynamics of a single polymer chain that is
pulled by a constant force applied at its one end with the other end free. Such
a situation is relevant to the growing technology of manipulating individual
macromolecules, which offers a paradigm research for probing
far-from-equilibrium responses of long flexible biological polymers. We first
analyze the Rouse model for the Gaussian chains for which the exact analytical
results can be obtained. More realistic features such as the finite
extensibility, the excluded volume and the hydrodynamic interactions are taken
into account with the help of the scaling argument, which leads to various
nontrivial predictions such as the stretching-force-dependent friction
constants. We elucidate (i) generalized dynamical equations of state describing
extension/friction laws in steady-state and (ii) the tension propagation laws
in the transient process. We point out that the time evolutions of the dynamic
friction in the transient process crucially depend on the experimental
protocol, i.e., either constant force or velocity ensemble, which might be
detectable in experiments using giant DNAs and chromosomes.
