Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1389111 | Carbohydrate Research | 2007 | 6 Pages |
Individual cellulose macromolecules were successfully visualized on a highly oriented pyrolytic graphite (HOPG) surface by tapping-mode atomic force microscopy under ambient condition. Monomolecular-level dispersion of cellulose chains was achieved through the momentary contact of dilute cellulose/cupri-ethylenediamine (Cu-ED) solution onto the HOPG substrate. Both concentrations of cellulose and Cu-ED provided critical impacts on the topographical images. Single cellulose chains with molecular height of ca. 0.55 nm could be observed under the optimal conditions, showing rigid molecular rods with a unique morphology of hexagonal regularity. It was strongly suggested that the cellulose chains were aligned along the HOPG crystal lattice through a specific attraction, possibly due to a CH–π interaction between the axial plane of cellulose and the HOPG π-conjugated system. These phenomena would imply the potential applications of an HOPG substrate for not only nano-level imaging, but also for molecular alignment of cellulose and other structural polysaccharides.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide