PhD Thesis

Monday, 04 January 2010 01:30 administrator

The title of my thesis is 'Self-assembly in complex systems', and can be read below the abstract on this page. Alternatively, a pdf version can be downloaded from here.


The work presented in this thesis investigates the relationship between anisotropy and self-assembly of complex morphologies. We present new coarse-grained potentials supporting self-assembly of anisotropic building blocks into a wide range of mesoscopic structures. To characterize model systems, we study the underlying energy landscapes.

Investigating the available parameter space for the model potentials in a systematic way reveals how the anisotropic shape and interactions define both the self-assembling character of the landscape and the morphology of low-energy structures. We employ single-site anisotropic, and multisite isotropic potentials separately and in combination for constructing the model mesoscopic building blocks.

For clusters composed of uniaxial disklike ellipsoids, we find a wide region of parameter space supporting spontaneous assembly into single- and multi-stranded helices. The emergence of such chiral structures can be explained by the symmetry breaking of perfectly stacked dimer configurations.

Among the low-energy structures identified for our coarse-grained model systems are helical stacks, icosahedral and non-icosahedral closed shells, double-shell assemblies, chiral and achiral open tubes, and more complex structures, such as tightly packed spirals similar to tobacco mosaic virus, and head-tail assemblies. We present the simplest, physically realistic model to date for viral capsid assembly.

We also study interconversion between competing structures, using atomistic models for an RNA hairpin, and a coarse-grained model for the dissociation of a virus capsid. The thesis concludes with a model for calculating binding free energies in ligand-receptor systems, based on global optimisation. Such complexes are another example of the importance of molecular shape and anisotropy for determining favourable morphologies.

Self-assembly in complex systems (PhD Thesis)

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Last Updated on Monday, 04 January 2010 23:16