The symmetrical twinning of solid domains of racemic mixtures of dipalmitoylphosphatidylcholine (DPPC) at the air-water interface is evidence that the solid domains are two-dimensional crystals; there are two equivalent axes in each domain that subtend an angle of approximately 120°. Fluorescence anisotropy shows that each domain has long-range molecular orientation order with ferroelectric symmetry. From the fluorescence anisotropy it is inferred that the in-plane electric moments of adjoining domains are more nearly antiparallel, rather than parallel. Experimental and theoretical evidence is presented to show that features of crystal structure such as molecular tilt depend on the size and shape of these two-dimensional crystals.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry