Abstract
Rod-like and sheet-like nano-particles made of desoxyribonucleic acid (DNA) fabricated by the DNA origami method (base sequence-controlled self-organized folding of DNA) are dispersed in a lyotropic chromonic liquid crystal made of an aqueous solution of disodium cromoglycate. The respective liquid crystalline nanodispersions are doped with a dichroic fluorescent dye and their orientational order parameter is studied by means of polarized fluorescence spectroscopy. The presence of the nano-particles is found to slightly reduce the orientational order parameter of the nematic mesophase. Nano-rods with a large length/width ratio tend to preserve the orientational order, while more compact stiff nano-rods and especially nano-sheets reduce the order parameter to a larger extent. In spite of the difference between the sizes of the DNA nano-particles and the rod-like columnar aggregates forming the liquid crystal, a similarity between the shapes of the former and the latter seems to be better compatible with the orientational order of the liquid crystal.
Highlights
Dispersing nano-particles (NPs) in a bulk matrix is a very promising strategy to develop new nanocomposites, i.e., tailored functional materials, which combine or even outperform the properties of their components
Rod-like and sheet-like nano-particles made of desoxyribonucleic acid (DNA) fabricated by the DNA origami method are dispersed in a lyotropic chromonic liquid crystal made of an aqueous solution of disodium cromoglycate
The respective liquid crystalline nanodispersions are doped with a dichroic fluorescent dye and their orientational order parameter is studied by means of polarized fluorescence spectroscopy
Summary
Dispersing nano-particles (NPs) in a bulk matrix is a very promising strategy to develop new nanocomposites, i.e., tailored functional materials, which combine or even outperform the properties of their components. If the matrix consists of a liquid crystal (LC) [1,2,3], i.e., an ordered fluid, the positions [4,5,6] or the orientation [7,8,9,10] of the nano-particles may be controlled by the LC structure. In the least ordered phase, the nematic (N). Phase, these units are preferentially aligned parallel, while their centers of gravity are randomly distributed. The preferred orientation of neighboring molecules or aggregates can be described by a pseudo vector n, the director, which can smoothly vary with position, depending on anchoring conditions and external electric or magnetic fields. The degree of parallel ordering can be described by Zvetkov’s scalar orientational order parameter
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