Entropy driven formation of a chiral liquid crystalline phase of helical rods

We study the liquid crystalline phase behavior of a concentrated suspension of helical flagella isolated from Salmonella typhimurium. With increasing concentration, a suspension of helical flagella undergo an entropy driven first order phase transition to a liquid crystalline state having a novel chiral symmetry. Flagella are prepared with different polymorphic states, some of which have a pronounced helical character while others assume a rod-like shape. We show that the static phase behavior and dynamics of chiral helices are very different when compared to simpler achiral hard rods.