Liquid-crystal imaging of molecular-tilt ordering in self-assembled lipid tubules.

Self-assembled cylindrical tubules of chiral phospholipids are interesting supramolecular structures. Understanding the molecular-tilt order is a key step in controlling the size and shape of the tubules and designing new functional materials. The current theories based on the chiral interactions, coupled with molecular tilt, have predicted that the tubules could have both uniform and modulated tilt states. Here, we image the molecular-tilt order in the self-assembled tubules of a chiral phospholipid by using liquid crystals as an optical amplification probe. We demonstrate that the organization of the molecular-tilt azimuth in the lipid tubules can induce an azimuthal orientation in the liquid crystals. Both uniform and modulated tilt states of the lipid tubules are observed after liquid-crystal optical amplification.