Tunable Order in Alginate/Graphene Biopolymer Nanocomposites

We report on highly aligned graphene oxide or graphene sheets inside an alginate matrix and their structure obtained for various compositions. The order of the platelet particles with respect to one another has been verified by environmental scanning electron microscopy (ESEM) and 2-dimensional X-ray diffraction (2D XRD). The microscopic order within the platelet particles has been analyzed by X-ray diffraction (XRD) measurements in the Bragg–Brentano reflection configuration as well as in Debye–Scherrer diffraction mode. The azimuthal angle intensity profiles obtained from 2D XRD analysis have been fit to Maier–Saupe and affine deformation model predictions, and the affine deformation model proved to be the most reliable to quantify the order parameter ⟨P2⟩ values of graphene oxide/sodium alginate and graphene/calcium alginate composites with different weight fractions of the filler. The ⟨P2⟩ values for graphene oxide/sodium alginate composites were found to show little dependence on the concentration of...