Anomalous elasticity of polymer cholesterics.

We show that polymer cholesterics have much longer pitches than comparable short molecule cholesterics, due to their anomalous elasticity. The pitch P of a chiral mixture with concentration c near the racemic (non-chiral) concentration c diverges like |c− c∗|−ν with, according to our very precise calculations [1], ν = 1.43 ± 0.04 (for short molecule cholesterics ν = 1). The short molecule law is recovered for polymers of finite molecular length l once the pitch is longer than a length that diverges like l with γ = 0.67± 0.01. Our predictions could be tested by measurements of the pitch in DNA [2].