Abstract
The aims of this work are twofold. They are 1) to develop an understanding of the conformational properties of gellan and related polysaccharides, and to relate this to rheological properties in solution, and 2) to investigate the roles played by different types of counter ions in the process of gellan gelation. Gellan and three related polysaccharides, welan, rhamsan and S-657 were investigated using molecular modelling. The results from these calculations provide structural information about these polysaccharides, which explain why only gellan is able to form gels. Molecular dynamics simulations with a range of different counter ions also yield possible mechanisms for the ion binding processes which are crucial to gelation. It has been possible to study the different types of ion binding between the gellan double helices, and this in turn has been related to the strength of gels induced by the various counter ions.