title: Refusing to twist: demonstration of a line hexatic phase in DNA liquid crystals
abstract: We report conclusive high resolution small angle x-ray scattering evidence that long DNA fragments form an untwisted line hexatic phase between the cholesteric and the crystalline phases. The line hexatic phase is a liquid-crystalline phase with long-range hexagonal bond-orientational order, long-range nematic order, but liquidlike, i.e., short-range, positional order. So far, it has not been seen in any other three dimensional system. By line-shape analysis of x-ray scattering data we found that positional order decreases when the line hexatic phase is compressed. We suggest that such anomalous behavior is a result of the chiral nature of DNA molecules.
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003 and NICHD/LPSB, National Institutes of Health, Building 12A/2041, Bethesda, Maryland 20892-5626, USA.
authors.initials: HH
authors.lastname: Strey
authors.initials: J
authors.lastname: Wang
authors.initials: R
authors.lastname: Podgornik
authors.initials: A
authors.lastname: Rupprecht
authors.initials: L
authors.lastname: Yu
authors.initials: VA
authors.lastname: Parsegian
authors.initials: EB
authors.lastname: Sirota