Scaling Theory of Stretched Polymers in Nanoslits

Abstract

We provide a scaling framework describing the different regimes attained by a slit-confined polymer, undergoing an external pulling force fel,slit. Linear and nonlinear force–extension relations are discussed in the limit of small and large elongations, resorting to the notion of self-avoiding pancakes. The crossover to a channellike behavior allows to explain the scaling of fel,slit as a function of the confinement h observed in recent tug-of-war experiments. The theoretical analysis provides also a qualitative explanation of DNA relaxation and coil–stretch transition experiments performed in nanoslits.