Abstract
Polymer nanostructured materials for drug delivery applications have witnessed tremendous progress in recent years due to their vast potential. One-end-grafted polymers can form grafted micelles with specific mechanical properties. Biological conditions can alter these properties resulting in the protection or release of drugs. Charged surfactants can also form micelles in an aqueous solution, which can also be manipulated through special conditions. On the micellar surface, self-organized polyelectrolytes can be stimulated to extend their attached ligands and thus increase the probability of binding to targeted receptors. This thesis focuses on modeling polymer-based drug delivery systems by studying the physical interactions between polymer segments under several biological conditions. Temperature, pH, salt concentrations, electrostatic charges and other biological conditions have been used as stimuli for polymer-based drug delivery applications. Different stimuli trigger multiple physical interactions (e.g. steric, van der Waals and electrostatic interactions), which are coupled with each other. The complex coupling between the physical interactions is studied by modeling thermodynamic systems composed of grafted polymers in a biological solution. A cubic lattice geometry has been used for modeling all studied thermodynamic systems. For each model, polymer self-organization is determined by generalizing a molecular theory based on a mean-field approach. These molecular theories determine the molecular organizations and the polymers aggregations in one or three-dimensional (1D or 3D) calculations. The theories are shown to form a design guideline for the creation of therapeutic polymer-based drug delivery devices.