Synthesis and characterisation of new tetrathiafulvalene-oligofluorene derivatives for moisture indicators
The term 'smart materials' refers to a category of materials that are able to dynamically respond to external stimuli through a change in physical and/or chemical properties. The versatility afforded by organic materials makes them attractive candidates in the development of new sensing materials. An in-depth understanding of the structure property relationships that drive a sensing material is a necessity in understanding device operation and reliably predicting their performance. Chapter 1 provides an overview of organic stimuli responsive materials and the types of physical properties that can induce a response in such materials. Chapter 1 further introduces the operating principles of sensors and their applications. Chapter 2 provides an introduction to the development of the novel hexylatedoligofluorene-thiophene systems wherein versatile 1,3-dithiole-2-one moiety is incorporated into the centre of the oligofluorene systems. The chapter follows a synthetic strategy used as a way to increase the dimensionality of oligofluorenesystems and discusses the influence of the synthetic strategy vis-à-vis yield and reproducibility of the systems. Chapter 2 further looks at the impact of the core uniton the photophysical behaviour of the oligofluorene spores and discusses the changes in the thermal and electronic properties of the new oligofluorene-thiophene systems as a consequence of the core unit. Chapter 3 discusses the development of new star-shaped oligofluorene-thiophene systems wherein redox-active dithiophene-tetrathiafulvalene is used as a core unit, providing an increase in dimensionality to a plurality of hexylated oligofluorenespores. The synthesis and properties of the oligofluorene systems are discussed. The photophysical behaviour, thermal and electronic properties of the new systems are investigated. Furthermore the core system displayed upon oxidation interesting features as fluorescence moisture indicator and are further investigated wherein the proof of concept is visible to the naked eye. The experimental procedures of chapters 2-3 are presented in chapter 4
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