Double twist in helical polymer "soft" crystals

In natural and synthetic materials having non-racemic chiral centers, chira lity and structural ordering each play a distinct role in the formation of ordered states. Configurational chirality can be extended to morphological chirality when the phase, structures possess low liquid crystalline order. In the crystalline states the crystallization process suppresses the chiral helical morphology due to strong ordering interactions, In this Letter, we report the first observation of helical single lamellar crystals of synthe tic non-racemic chiral polymers. Experimental evidence shows that the molec ular chains twist along both the long and short axes of the helical lamella r crystals, which is the first time a double-twist molecular orientation in a helical crystal has been observed.