8.592 - HST.452J (Spring 2025)

Statistical Physics in Biology

Lecture 8

Statistical Physics of Polymers

1. Polymers are long covalently bonded macromolecules, with N>>1 monomers
• Biological polymers: Polynucleotides, polypeptides, polysaccharides
• Homopolymers, heteropolymers
• Artificial polymers, e.g (-CHH-)N
2. How straight is a polymer?
• Thermal excitation of rotational isomores
• Bending rigidity and Persistence length
3. Entropic elasticity:
   • Random walks, Kuhn segments, and the central limit theorem
   • Polymer spring
4. Interactions:
   • Excluded volume; role of solvent
   • Mean-field estimate of the partition function

(Lecture notes)