Networks of helix-forming polymers (pdf)

Samuel Kutter and Eugene M. Terentjev
Eur. Phy. J E 8 539 (2002) and cond-mat/0207162

Biological molecules can form hydrogen bonds between nearby residues, leading to helical secondary structures. The associated reduction of configurational entropy leads to a temperature dependence of this effect: the "helix-coil transition". Since the formation of helices implies a dramatic shortening of the polymer dimensions, an externally imposed end-to-end distance R affects the equilibrium helical fraction of the polymer and the resulting force-extension curves show anomalous plateau regimes. In this article, we investigate the behaviour of a crosslinked network of such helicogenic molecules, particularly, focusing on the coupling of the (average) helical content present in a network to the externally imposed strain. We show that both an elongation and compression can lead to an increase in helical domains under appropriate conditions.