Block copolymers are widely used commercially and so a complete understanding of these systems requires that the nature of the polymer interface, the effect of deformation and the interaction between polymer substituents are known. Triblock copolymers of poly(styrene-isoprene-styrene) were synthesised and used in a Small Angle Neutron Scattering (SANS) study of deformation (Ch. 3) . Three sets of samples were made and, of these, two sets were found to have degraded giving unexpected results (Ch. 3.2). The third set, SPH150 series, however, did exhibit the expected anisotropy on deformation (Ch. 3.3). In these samples, the extension parallel to the stretch direction was affine for all elongation ratios studied and, perpendicular to the stretch direction, the extension was non-affine. The interaction between polymer substituents was examined using SANS on an isotopic diblock copolymer of polystyrene to ascertain if the mixing of hydrogenous and deuterated species was ideal (Ch. 4) . The results obtained showed the mixing between these species could be assumed to be ideal. The nature of the polymer-polymer interface was studied on the CRISP reflectometer using poly(styrene- isoprene) diblock samples (Ch. 5) . The results obtained for unannealed samples showed that a 'pseudo- equilibrium' had been achieved in these samples which was lost on annealing.

An AB2 monomer, dimethyl 5-(2-hydroxyethoxy)isophthalate was prepared on a scale of 3kg. It was successfully polymerised in the melt and the influence of reaction conditions and catalysts was studied. Structural and physical characterisation of these materials was performed using variety of analytical techniques, including SEC and MALDI-TOF MS. The polymerisations yielded high molecular weight materials with a broad polydispersity. All polymers were cyclised, the proportion of cyclised species increased with time, generally until complete cyclisation was achieved. The polymerisation process conditions were varied and a reaction protocol establishing a degree of reproducibility was achieved. Catalysts were found to promote polycondensation, cyclisation and transesterification reactions. The trends of increase in molecular weights were similar to those observed in uncatalysed reactions. Catalysts based on divalent metals showed a higher activity compared to those based on tri- and tetravalent metals. Qualitatively alcoholysis and cyclisation occurred at about the same rate whether catalysed or uncatalysed and ester-ester interchange was significantly slower under all circumstances. There were only relatively small differences between the effects of the catalysts investigated, apart from Vertec 400AC, which caused very fast reaction and yielded an insoluble product of unidentified structure. A new route to the synthesis of an A(_2)B monomer, methyl 3,5-bis(2-hydroxyethoxy)benzoate, was also reported. The monomer was synthesised on a 10g scale and successfully polymerised. The polymer samples were functionalised with acetoxy groups and characterised by SEC and MALDI-TOF MS. Evidences for the presence of polycondensation, cyclisation and ester-ester interchange reactions were observed. Growth in molecular weights and in cyclisation for poly(methyl 3,5-bis(2-hydroxyethoxy)benzoate)s was faster than that for poly(dimethyl 5-(2-hydroxyethoxy)isophthalate)s prepared under same conditions.

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Tissue engineering requires diagnostic tools for in-vitro monitoring of cell proliferation in three-dimensional scaffolds. Current methods are inaccurate, prohibitively expensive, or compromise sample integrity. This work presents a nondestructive system for the on-line measurement of cell concentration in micro-porous polymer scaffolds. The system is based on measuring the reflection coefficient of the sample with an open-ended coaxial probe over a frequency range of 10-200 MHz. An aperture admittance model is used to extract the complex permittivity from the reflection measurement. Then, effective medium approximation is used to relate the complex permittivity to the cell properties and concentration of the sample. / The system detected the relative cell concentration differences between micro-porous polymer scaffolds seeded with progressively greater number of pre-osteoblast cells. Proliferation of pre-ostoblasts over 14 days was measured within 56 scaffolds by the system and a concurrent DNA assay. The recorded cell proliferation data corresponded well to each other and those found in literature. Thus, the system can be applied for on-line monitoring of cell proliferation within micro-porous polymer scaffolds.

The crystallization of poly(ethylene oxide) (PEO) in blends with amorphous poly(vinyl chloride) (PVC), in a mixture with the PVC-selective plasticizer tricresyl phosphate (TCP), and in ternary mixtures with both PVC and TCP has been investigated at several structural levels using the techniques of: (i) theoretical surface interfacial tension calculations, (ii) thermal analysis, (iii) polarized light microscopy, and (iv) polarized infrared microspectroscopy. / The invariance of the glass transition temperature of the interlamellar, amorphous PEO suggests a relatively low degree of dispersion in PEO/PVC blends. A slight depression in the equilibrium melting temperature of PEO in blends of high PVC content was observed, and subsequent analysis of the data using the Flory-Huggins equation reveals that, at best, PEO and PVC exhibit limited miscibility in the melt. The melting temperature depression may be accentuated by the addition of TCP, but the depression observed in the ternary mixtures lies within the experimental uncertainty. / In general, the spherulites grown in the presence of additives are coarser and less birefringent than those grown in the pure melt, with the degree of coarseness increasing with increasing additive concentration. The interpretation of the crystallization kinetics of PEO using current nucleation theory clearly demonstrates that the crystallization of PEO in the temperature range of interest occurs within regime III. The slight kinetic discontinuity at $ sim$51$ sp circ$C that has been thought to arise from a regime II/III transition can be attributed to a transformation of the dominant crystal growth face from the (010) crystallographic face at lower temperatures to the (120) face at higher temperatures. The growth rates of PEO spherulites in PEO/PVC blends are not affected by the presence of PVC in the temperature range 49-55$ sp circ$C, even at concentrations as high as 50% PVC. However, the growth rates of spherulites in mixtures containing TCP are significantly depressed. / Dichroic infrared microspectroscopy was employed to investigate the variations in the crystalline structure at the sub-spherulitic level. The determination of the dichroic ratios and the selected peak ratios from the spectra of purely crystalline PEO (obtained by difference spectroscopy) reveals that PVC disturbs the orientation of the crystalline stems of PEO within the spherulites and causes an increase in the crystallization of PEO in the strained, planar zig-zag conformation. PEO, in turn, appears to induce a higher incidence of the planar zig-zag conformation in the PVC molecules. In the ternary mixtures, the plasticizing effect of TCP on PVC renders the PVC molecules more flexible and more mobile, thereby drastically reducing the shearing of the PEO and the resultant formation of the planar zig-zag conformation during crystallization. In effect, the crystallization kinetics and the basic crystalline structure of PEO can be controlled by selection of appropriate proportions of PVC and TCP, a result of major significance and practical importance to the field of polymer blends.

Quantum-confined semiconductors have been synthesized in ionomer microdomains, demonstrating thermodynamic control of nanoparticle sizes via a priori knowledge of ion aggregation numbers. In block ionomers, cadmium sulfide (CdS) nanoparticle sizes are found to scale with the ionic block length (N B) as NB3/5. CdS-polymer composites from block ionomers can be suspended in organic solvents as reverse micelles. Micelle stability is improved by reneutralization of acrylic acid blocks surrounding the nanoparticle. Reloading of microreactors and controlled continued growth of nanoparticles is demonstrated. Novel assemblies of CdS-containing reverse micelles are formed by secondary self-assembly in aqueous media. Scaling relations are also determined for microreactors containing different metal ions. For all metal ions investigated, the ionic core size scales as NB0.58+/-0.03, in agreement with starlike models; the proportionality constant is found to depend on the metal ion. / Coronal structure in block ionomers has been investigated by small-angle neutron scattering (SANS), using deuterated labels at various distances from the ionic core. Near the outside of the polymer brush, the scattered intensity scales with the scattering vector (q) as q --5/3, suggesting a semidilute environment for the label. Chain conformations are influenced by neighbouring coronae above the micelle overlap concentration. Closer to the ionic core, the chains become more crowded, and the semidilute assumption is not applicable. For labels directly connected to the core, intensity scaling suggests highly extended chains.

A detailed analysis of the crystallization behaviour of poly(dimethylsiloxane) (PDMS) was undertaken. Determination of the equilibrium melting temperature showed a six degree difference between the equilibrium melting of a hydroxy terminated polymer (PDMS-OH, Tmo = 266 K, M w = 92.9 kg mol-1) over that of a trimethylsilyl terminated polymer (PDMS-CH3, Tmo = 260 K, Mw = 100 kg mol-1). The inherent flexibility of the Si-O linkage of these polymers caused crystallization to be first detected at Tmo - 35 K, and was recorded down to 177 K, i.e., Tg + 30 K. Both systems followed well behaved regime III surface nucleation kinetics. The average fold interfacial surface free energy, sigmae, was calculated to be 17.6 erg cm -2 and resulted in a very low value for the work of chain folding, q, calculated to be 14.6 kJ mol-1. This is in accord with the small rotational barrier of the siloxane backbone. In addition, PDMS-OH crystallized with slower kinetics than PDMS-CH3, verified by chemical conversion from the hydroxy to trimethylsilyl end group. / The first reported detection of two different PDMS solid state morphologies is presented. A small population of very low birefringent (Deltan ) spherulites was observed to nucleate simultaneously with a majority of bright positive Deltan spherulites throughout the accessible crystallization temperature range. The sign of Deltan of these darker spherulites varied with growth, and this growth rate was depressed from that of the bright spherulites. Calorimetric annealing experiments indicate that the PDMS system attains very high percent crystallinities very early after nucleation. Coupled with the results of small angle laser light scattering (SALLS) during slow (1 deg/min) melting, secondary crystallization processes were observed to be non-negligible very soon after primary crystallization. / SALLS of the crystallizing PDMS system was sensitive to the concurrent effects of (i) the presence of dark spherulites, (ii) secondary crystallization, and (iii) the distribution of spherulite sizes. These combined effects generated significant non-ideality within V v and Hv scattering envelopes. The effects of (i) and (ii) caused both the Vv pattern to remain circularly symmetric throughout the entire crystallization timeframe, and the 4-leaf clover pattern of the Hv mode scattering to contain multiple intensity maxima not restricted to an azimuthal angle of 45°. The effect of (iii) was to lower the calculated SALLS average radial growth rate relative to that observed optically.

The solid state morphology of block copolymers containing short ionic terminal sequence(s) was investigated using small-angle X-ray and neutron scattering (SAXS and SANS) as a function of architecture (AB, ABA), chemical composition of the ionic block(s) (vinylpyridinium, cesium methacrylate), length of the ionic and nonionic (polystyrene) blocks, extent of neutralization, and method of preparation (compression molding, solvent casting). The ionic phase-separated microdomains were found to be spherical. The radius of those spheres depends only on the length of the ionic block and not on any other of the parameters studied. The only exceptions were the molded ABA vinylpyridinium materials which were thought not to be in their equilibrium morphology due to the method of preparation. The ionic blocks seem highly extended in their microdomains. This is explained by the fact that the system is producing the biggest possible spheres in order to minimize the total interfacial energy. It was also found that the AB architecture and the preparation by solvent casting favor ordering of the microdomains. / The conformation of the polystyrene midblock in ABA vinylpyridinium materials in the solid phase was studied by SANS. The dimensions of this segment were clearly found to be identical to a homopolymer of the same molecular weight, indicating that no stretching occurs due to the presence of the two attached ionic blocks.

In this thesis, I have produced low polydispersity polymers of poly(chloromethylstyrene) and polyvinylphenol. Modification reactions for both polymers were attempted and were successful for only poly(chloromethylstyrene) as conditions in our experiments produced insoluble polymer salts using polyvinylphenol. A set of modified polymers were produced using a low polydisperse poly(chloromethylstyrene) as we believe that polymers with PDIs < 1.4 will be preferable for use in an eventual solar cell device. Finally a set of experiments were completed to determine the conditions to minimize the PDI of poly(chloromethylstyrene) and found that the main variable was maximizing the amount of 3-chloromethylstyrene with respect to 4-chloromethylstyrene in a polymerization. This result has lead us to believe that 3-chloromethylstyrene is less prone to transfer reactions, which in turn leads to smaller PDI values.

In this thesis, I have produced low polydispersity polymers of poly(chloromethylstyrene) and polyvinylphenol. Modification reactions for both polymers were attempted and were successful for only poly(chloromethylstyrene) as conditions in our experiments produced insoluble polymer salts using polyvinylphenol. A set of modified polymers were produced using a low polydisperse poly(chloromethylstyrene) as we believe that polymers with PDIs < 1.4 will be preferable for use in an eventual solar cell device. Finally a set of experiments were completed to determine the conditions to minimize the PDI of poly(chloromethylstyrene) and found that the main variable was maximizing the amount of 3-chloromethylstyrene with respect to 4-chloromethylstyrene in a polymerization. This result has lead us to believe that 3-chloromethylstyrene is less prone to transfer reactions, which in turn leads to smaller PDI values.