Stretching of a polymer below the theta point

Phys Rev Lett. 2003 Feb 28;90(8):088301. doi: 10.1103/PhysRevLett.90.088301. Epub 2003 Feb 25.

Abstract

The unfolding of a polymer below the theta point when pulled by an external force is studied both in d=2 on the lattice and in d=3 off the lattice. At T=0 and for finite length chains, it is found that the globule unfolds via multiple steps, corresponding to transitions between different minima, in both cases. In d=3 one of these intermediates is a regular helix. In the infinite length limit, these steps have a qualitative effect only in d=2. The phase diagram in d=2 is determined via the transfer matrix. To rationalize these results, energy-entropy and renormalization group arguments are given.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biopolymers / chemistry*
  • DNA / chemistry
  • Models, Chemical*
  • Nucleic Acid Conformation
  • Protein Folding
  • Stress, Mechanical
  • Temperature

Substances

  • Biopolymers
  • DNA