Helix-coil transitions of dilute polymers under a velocity gradient

Abstract

A theoretical model of helix-coil transitions of polymers such as polypeptides under a velocity gradient is presented. A polymer in dilute solution is represented by a chain of alternating flexible coils and rigid rods which represent flexible segments and helical segments respectively. A time-independent homogeneous velocity gradient is introduced and the effects on the conformational properties of polymers are investigated. The numerical analysis of the model shows that if a velocity gradient is not too small, the effects are significant and considerable changes of conformational properties of polymers arise. In the latter part of the paper, the effects of the anisotropic excluded volume type interactions between helical segments are included in the model by a mean field approximation