The surfaces of well characterised microfibrils from Ventricaria and Micrasterias denticulata (M.d.), wood sections, kraft pulp fibres and paper have been examined with both atomic force microscopy (AFM) and Tapping Mode atomic force microscopy (TM-AFM), under ambient conditions in both air and water. Artifacts and limitations inherent to these techniques in the study of microfibrils, pulp fibres and paper are discussed. AFM images of the surface of the highly crystalline cellulose microfibrils, Ventricaria and M.d., were obtained at molecular resolution under ambient conditions; the molecular images showed periodicities along the microfibril axis that correspond to those of the fibre and glucose unit repeat distances of cellulose, respectively. Images of the section surface of Black Spruce (Picea mariana) wood clearly show features of the underlying cell wall structure. The apparent lamellation, with periodicities from tens or nanometers down to 15 nm, were observed in radial sections of the middle secondary wall (S2). However, transverse sections of the same S2 layer did not show a lamellation independent of the knife direction. AFM images of unbeaten and beaten unbleached kraft pulp fibre surfaces indicate the orientation of the component microfibrils; fibrillar material attached to the surface of the beaten fibres was readily observed. Images from the scale of the fibre web down to the microfibril level in air and water show the dimensional changes of the paper surface and fibres. However, little or no change was seen at the microfibril level. The dimensions of the lamella in wood sections and the size of the microfibrils at both the surface of pulp fibres and the fibrillated material indicate that microfibrils as small as 1.5 nm across are present.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.40030 |
| Date | January 1995 |
| Creators | Hanley, Shaune J. (Shaune John) |
| Contributors | Gray, D. G. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001499052, proquestno: NN19923, Theses scanned by UMI/ProQuest. |
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