The effect of added co-solvent on the phase behaviour of the micellar liquid crystal system caesium pentadecafluorooctanoate/water : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University

Simple item page
dc.contributor.authorThomsen, Scott Jonathan
dc.date.accessioned2019-08-19T01:34:40Z
dc.date.available2019-08-19T01:34:40Z
dc.date.issued1994
dc.description.abstractThe effect of the addition of the co-solvents formamide (FA), N-methylformamide (NMF), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA) on the phase behaviour of the micellar liquid crystal system caesium pentadecafluorooctanoate (CsPFO)/D2O (weight fraction CsPFO=0.5) has been determined. In all cases the effect of the addition of co-solvent is to decrease the isotropic (!)-to-nematic (N ) and the nematic - to - lamellar (Lo) phase transition temperatures. At a co-solvent mole fraction of 0.01 the observed decreases in the I-to-N phase transition temperatures (TNI) were 5.3 K, 15.5 K, 15.7 K, and 18.8 K for the co-solvents FA, NMF, DMF, and DMA respectively, whilst the corresponding decrease for the N -to-Lo phase transition temperatures (TNL) were 5.5 K, 16.1 K, 16.3 K, and 19.1 K. Thus, at low co-solvent concentrations, the main effect is simply to displace the phase transition lines to lower temperatures and there is no significant change in the overall phase behaviour other than a small increase in the temperature range of the N phase. 2H NMR measurements reveal that, in all cases, increasing the co-solvent concentration at constant temperature results in concomitant decreases in micelle aggregation numbers but the micelle sizes at TNI and those at TLN are essentially the same, i.e. the phase transitions are determined by hard particle interactions. Thus, the effect of co-solvent on the phase behaviour can be understood in terms of changes in micelle self-assembly, with addition of co-solvent shifting the distribution of micelle sizes to a lower mean aggregation number and decrease in temperature shifting the distribution of micelle sizes to a higher one. NMF, DMF, and DMA have a much greater effect on micelle size distribution than does FA.en_US
dc.identifier.urihttp://hdl.handle.net/10179/14881
dc.language.isoenen_US
dc.publisherMassey Universityen_US
dc.rightsThe Authoren_US
dc.subjectLiquid crystalsen_US
dc.subjectSpectraen_US
dc.titleThe effect of added co-solvent on the phase behaviour of the micellar liquid crystal system caesium pentadecafluorooctanoate/water : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey Universityen_US
dc.typeThesisen_US
massey.contributor.authorThomsen, Scott Jonathan
thesis.degree.disciplineChemistryen_US
thesis.degree.grantorMassey Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Science (M. Sc.)en_US
Files
Original bundle
Now showing 1 - 2 of 2
Thumbnail Image
Name:
01_front.pdf
Size:
328.09 KB
Format:
Adobe Portable Document Format
Description:
Download
Thumbnail Image
Name:
02_whole.pdf
Size:
1.46 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
3.32 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Theses and Dissertations