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Solid-state NMR has become a powerful tool for studies of structural and physical properties of polymers. This thesis investigates a technically produced block copolymer . by means of solid-state NMR. The properties which are of principal interest are the heterogeneity on various scales ranging from molecular (unit cell) to macroscopic (morphology), and molecular motion in solids. The important question of cross polarisation is addressed. Quantification of depolarisation experiments will bring some more insight into the origins of the polarisation transfer. Basically a model by Muller, Kumar and Ernst has been used to describe the polarisation transfer. Novel results are reported in this area spin-lattice relaxation measurements, both in the laboratory and on-resonance rotating frames of resonance are applied to the block copolymer. An attempt is made to address the relation of the observed relaxation times and the macroscopic properties. The behaviour of the observed and the intrinsic properties of the various regions of the heterogeneous system in the presence of spin diffusion is investigated. The system is simulated by a computer model, which allows quantification of the dimensions of the different regions. Comparison with small-angle X-ray diffraction measurements illustrates the accuracy of this new powerful technique.

The non-crystalline, nature of supramolecular assemblies makes it difficult to investigate their structures by traditional methods such as X-ray crystallography. On the other hand, solid-state nuclear magnetic resonance (NMR) spectroscopy, a fast-developing technique that mainly detects the local atomic environment, is suitable for this purpose. In this dissertation, we start with a brief introduction in Chapter 1, then focus on the application of solid-state NMR spectroscopy on a few peptide and protein supramolecular assemblies that have biological significance: amyloid fibrils formed by deletion mutants of human prion protein (huPrP) 23-144 in Chapter 2, peptide amphiphile (PA) palmitoyl-VVAAEE-NH2 nanofibers in Chapter 3, and nanofibrils and aggregates of several peptide-chromophore-peptide triblock compounds in Chapter 4. One- and two-dimensional high-resolution magic angle spinning (MAS) solid-state NMR spectroscopy was employed to fast access the conformation and dynamics of these assemblies. Inter-atomic distances were further measured by dipolar recoupling pulse sequences. Other methods, such as transmission electron microscopy (TEM) and atomic force microscopy (AFM) to characterize the morphology of the supramolecular assemblies, X-ray diffraction to measure the interlayer distance, as well as thioflavin T fluorescence assay to monitor the kinetic of amyloid fibril formation, were also largely involved in the dissertation. We have found the shortest fragment of huPrP23-144 that can be expressed at reasonable yield in E. coli and retain the wild-type like amyloid folding. For the PA and peptide-chromophore-peptide triblock compounds we studied, parallel, in-register ß-sheet structure largely exist even for one compound that only forms small, random aggregates. Polymorphism was observed to exist extensively in both PA and the p-conjugated peptides. DRAWS to measure the homo-nuclear distance and TEDOR to measure the hetero-nuclear distance were proven to be two useful experiments to study the stacking in the self- and co-assemblies. Our results can facilitate the understanding of huPrP23-144 amyloid structure and the mechanism of relevant prion diseases, as well as promote more rational design of peptide-based materials that have novel supramolecular structures.