This thesis presents three experimental studies using model suspensions of dye-doped colloidal sepiolite clay rods. In all cases, dye molecules adsorbed onto the outer surfaces of the rods were removed by Soxhlet extraction, yielding dye-doped rods which were then sterically stabilised in toluene. The liquid crystalline phase behaviour of these rods was examined and was similar to that observed previously for undyed particles. The isotropic-nematic phase boundary was as expected for hard spherocylinders of the same aspect ratios; however the transition was broadened due to polydispersity of the rods. Aligning the dyedoped rods in a 9 T magnetic field resulted in a single-domain nematic phase with a marked dichroism. This was due to the restricted orientations of the dye molecules within the zeolitic channels of sepiolite. The order parameter of the dye in the aligned colloidal rods was up to 0.5, similar to typical values for dye in aligned molecular liquid crystals.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:503864 |
| Date | January 2009 |
| Creators | Yasarawan, Nuttawisit |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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