The main objective of this thesis is to establish the main factors which control the sensitivity of thin-film oxygen optical sensors. In Chapter 1 the main sensing principles and the main classes of oxygen-sensitive lumophores are described. Numerous examples are given describing the major developments in oxygen sensors. Finally, research areas of interest are outlined. Chapter 2 describes the experimental methods and the chemicals used in this work. In Chapter 3 the incorporation of the lumophore tris (4,7-diphenyl-1,10-phenanthroline) ruthenium (II) ditetraphenylborate, [Ru(dpp)<SUB>3</SUB><SUP>2+</SUP> (Ph<SUB>4</SUB>B<SUP>-</SUP>)<SUB>2</SUB>], in different polymer-plasticizer matrices is described. The sensitivity of the sensor depends upon the nature of the polymer matrix and plasticizer. A detailed study of a highly plasticized system utilising the polymer poly(methyl methancrylate), PMMA, is reported. In Chapter 4, the properties of two highly plasticized oxygen sensors are investigated using [Ru(dpp)<SUB>3</SUB><SUP>2+</SUP> (Ph<SUB>4</SUB>B<SUP>-</SUP>)<SUB>2</SUB>], and dichlorobis (4,7-diphenyl-1, 10-phenanthroline) iridium (III) tetraphenylborate, [Ir(dpp)<SUB>2</SUB>Cl<SUB>2</SUB><SUP>+</SUP> (Ph<SUB>4</SUB>B<SUP>-</SUP>)] in the most sensitive polymer and plasticizer combination reported in Chapter 3, <I>i.e.</I> cellulose acetate butyrate polymer-tri-n-butyl phosphate plasticizer (CAB-TBP). In Chapter 5 the oxygen quenching and natural lifetime of tris (2,2'-bipyridyl) ruthenium (II) ditetraphenylborate, [Ru(bpy)<SUB>3</SUB><SUP>2+</SUP>(Ph<SUB>4</SUB>B<SUP>-</SUP>)<SUB>2</SUB>], is studied in a variety of neat plasticizers, in unplasticized and TBP plasticized CAB and PMMA oxygen sensors. The compatibility of the polymer and plasticizer is considered in relation to the oxygen sensitivity of the sensors. In Chapter 6, a pyrene lumophore is used as a polarity probe and as an oxygen sensor. The polarity of the encapsulating medium and the sensitivity of the sensors is studied. Reasons for the lack of correlation between the increase in sensitivity and the polarity of the encapsulating medium, measured using pyrene as the probe, are discussed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:639196 |
| Date | January 1998 |
| Creators | Thomas, M. D. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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