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The direct covalent attachment of conducting polymers (CP) to nanoparticles (NP) to form CP-NP nanohybrids is of great interest for optoelectronic device applications. Hybrids formed by covalently anchoring CP to NP, rather than traditional blending or bilayer approaches, is highly desirable. CP-NP nanohybrids have increased interfacial surface area between the two components, facilitating rapid exciton diffusion at the p-n heterojunction. These materials take advantage of the facile solution processability, lightweight characteristics, flexibility, and mechanical strength associated with CPs, and the broad spectral absorption, photostability, and high charge carrier mobility of NPs. We demonstrate the ability to polymerize a hole transporting (HT) polymer utilizing reversible-addition-fragmentation chain transfer (RAFT) polymerization and its subsequent rapid aminolysis to yield a thiol-terminated HT polymer. Subsequent facile attachment to gold (Au) and silver (Ag) NPs and cadmium selenide (CdSe) quantum dots (QDs), to form a number of CP-NP systems is demonstrated and characterized. CP-NP nanohybrids show broad spectral absorptions ranging from UV through visible to the near IR, and their facile synthesis and purification could allow for large scale industrial applications.

This thesis is entitled 'Exotic Monoliths', which has been defined, in the context of this thesis, as monoliths; (1) synthesised by methods not previously described in the literature, (2) synthesised from commonly used silica or organic polymer materials but whose surface has been modified with a novel material such as dyes, nano-particles and biologically active compounds, and (3) synthesised from materials which are not based on silica or organic polymers, such as zirconia or titania. The first two of these definitions have been the main focus for this thesis. The thesis itself comprises five chapters. Chapter 1 presents an introduction to polymer monolith stationary phases and a detailed summary of the many different methods of synthesis. The surface modification of the monoliths and their applications in separation science, along with a short comparison with particle packed columns and introduction to some more novel inorganic monoliths is also presented. Following on from this, Chapter 2 shows the preliminary work carried out on synthesising monoliths in capillary. Presented in this chapter is an investigation of thermally initiated polymerisation in standard 100 μm i.d. capillary and in larger diameter fused silica and PEEK capillary moulds. Photo-initiated polymerisation using both conventional UV lamps and light emitting diodes is also investigated, along with a novel application of LED synthesised monoliths, i.e. using short plugs of monoliths as retaining frits for column packing. Finally a short study of the ability to reproduce literature methods of surface modification by successfully grafting a layer of methacrylic acid and 2-aminoethyl methacrylate on the surface of a monolithic scaffold is shown. Chapter 3 presents the research carried out on the modification of organic polymer monoliths with photochromic dyes and the synthesis of monoliths directly from modified photochromic dyes with a polymerisable double bond. A novel application of these photochromic monoliths is their use as photo-switchable electroosmotic pumps allowing eluent flow to be controlled by light in micro-fluidic devices, which is also presented in this chapter. It is shown that by switching the wavelength of irradiation from visible to ultraviolet an increase or decrease, respectively, in the flow rate can be observed. The final two chapters, 4 and 5, present novel methods of monolith synthesis using light emitting diodes in the visible region. Chapter 4 looks at the polymerisation of methacrylate monomers within polyimide coated moulds using red light while Chapter 5 looks at the polymerisation of styrenic monomers in poly(tetrafluoroethylene) coated capillaries using blue light emitting diode arrays. In both cases the characterisation and application of the synthesised monoliths is presented showing that they are suited to use in separation science. The suitability of this method to polymerise monoliths in chips moulds was also shown, as was the ability of the initiation system activated by red light to be used for the photo-initiated grafting of chromophoric monomers. A final section entitled 'General Conclusions and Outlook' provides a summary of the thesis and areas for further work.

Novel functional materials offer unique capabilities hitherto inaccessible using conventional materials. In particular, we focus on photo-controlled guest binding and release, inherent signalling of status, photo-actuation and solvent driven motion of small structures as examples of the fascinating behaviour of these exceptional materials. We have shown that by integrating the beneficial characteristics of PDMS micro-fluidic devices and spiropyrans dyes, a micro-chip configured as an on-line photonically controlled selfindicating system for metal ion accumulation and release can be realised. Moreover, spiropyran functionalised micro-beads were incorporated into micro-fluidic flow systems, such as capillary separation columns. In addition, photochromic monolithic scaffolds were synthesised within polytetrafluoroethylene coated fused silica capillaries and used as stationary phases in micro-chips to function as photo-controllable electro-osmotic pumps. Novel multifunctional materials based on ionogels, consisting of a polymeric structure incorporating spiropyran units and phosphonium based ionic liquids, have been used as light-actuated valve structures in micro-fluidic platforms. Through variation of the composition of the ionogels, the micro-valves can be tuned to open at different times under similar illumination conditions. In parallel, the ionogels were soaked in ethanol and then transferred to water, where they moved spontaneously. This movement is driven by the expulsion of the ethanol from the gel and subsequent ethanol spreading at the air-water interface. We have investigated this solvent driven motion for as a driving force for moving small objects in aqueous media. We have also developed an innovative miniaturised system for continuous measurement of the pH of sample solutions and vapour streams during chemical or biological processes. It consists of a simple barcode sensor with several pH dyes doped in an ionogel matrix which is able to generate a characteristic fingerprint-type colour response within a single “snapshot” for different pH solutions and vapours. As the sensor is based on an ionogel polymer, it has extremely long stability, and the sensor dyes show no measureable leaching into aqueous sample solutions. Finally a wearable, robust, flexible and disposable micro-fluidic device which incorporates micro-Light Emitting Diodes (μ-LEDs) as a detection system, for real time monitoring of the pH of sweat generated during an exercise period has been fabricated and assessed. In our approach, the sensors are immobilised within ECG electrodes, as this allows the pH measurements to be gathered without changing the conventional form of ECG monitoring during exercise. This provides immediate feedback regarding sweat composition to an athlete and coach, which can be used to optimise the hydration and performance of the athlete.

Spiropyran is a well known family of photochromic compounds presenting the peculiar feature of being able to change their physical and chemical properties under external light modulation [1]. It has been demonstrated that even low-power light sources such as light emitting diodes (LEDs) can switch spiropyran molecules between an non-polar, uncoloured spiro form (SP) and a strongly coloured, zwitterionic merocyanine form (MC), which also possesses a phenolate binding site for metal guest species such as Cu2+ [2] and Co2+ [3], using white or UV light, respectively. MC-bound metal ions can be subsequently released using a green LED light source which converts the binding-MC back to the passive SP form [4]. The incorporation of spiropyran derivatives or spiro-modified substrates into flow micro-systems opens up intriguing possibilities for creating stationary phases whose binding behaviour can be externally modulated using light. We investigated this idea using two approaches. In one case, the stationary phases were generated by packing spiropyran functionalised silica and polystyrene microspheres [5] into polytetrafluoroethylene (PTFE)-coated fused silica capillaries (100 μm inner diameter). In the second, spiropyran compounds were used to create new monolithic stationary phases, using both a spiropyran monomer to synthesise a SP-derivatised monolith directly in silica capillaries, and a post-synthesis functionalisation strategy wherein the spiropyran is immobilised on the monolith’s inner surface after it has been formed in-situ. These SP-modified stationary phases have indeed shown light-induced reversible ion-binding capability (functionalised microspheres) and light-modulated electroosmotic nanoflow (spiropyran monoliths). In this talk the creation of these stationary phases and their light-modulated behaviour will be discussed. References [1] Durr, H.; Bouas-Laurent, H. Eds, Photochromism: Molecules and Systems, Elsevier, Amsterdam, 2003 [2] Shao, N.; Zhang, Y.; Cheung, S.; Yang, R.; Chan, W.; Mo, T.; Li, K.; Liu, F. Anal. Chem., 2005, 77, 7294-7303. [3]. Byrne, R.; Stitzel, S.; Diamond, D. Mat. Chem., 2006, 16, 1332-1337 [4]. Radu, A.; Scarmagnani, S.; Byrne, R.; Slater, C.; Lau, K. T.; Diamond, D., J. Physics D: Applied Physics 2007, 23, 7238-7244 [5] Scarmagnani S.; Walsh Z.; Slater C.; Alhashimy N.; Paull B.; Macka M.; Diamond D., J. Mat. Chem., 2008, 18, 5063 – 5071.

Microfluidic chips are particularly attractive for analytical purposes because they provide a convenient small platform for rapid analysis and detection.1 Furthermore, spiropyrans dyes can be used as photonically controlled, self-indicating molecular recognition agents for the fabrication of sensors.2 Here, we show how through integrating the beneficial characteristics of microfluidic devices and spiropyrans dyes, a simple and very innovative chip for on-line metal ion sensor array can be realised. The chip (4x3cm) consists of four independent 180m depth, polydimethylsiloxane (PDMS) channels. 1’-(3-Carboxypropyl)-3,3’-dimethyl-6-nitrospiro-[2H-1]-benzopyran-2,2’-indoline is covalently immobilised on the ozone plasma activated PDMS microchannel surfaces. Upon exposure to UV light, the transparent PDMS channels change to light purple colour because the spiropyran molecules of the surface undergo a heterocyclic ring cleavage that result in the formation of the highly conjugated merocyanine form. When stock solutions of several ion metals (Ca2+,Zn2+,Hg2+,Cu2+) are pumped independently through the four channels, different optical responses were observed for each metal. 1-L.Basabe-Desmonts et al. Anal.Bioanal.Chem.(2008)390:307–315. 2-R.J.Byrne et al. J.Mat.Chem.(2006)16:1332-1337.