9320196 Gibson A "polyrotaxane" consists of cyclic molecules physically threaded onto a linear macromolecule with no covalent bonds between the cyclics and the linear backbone; bulky end groups may be fitted to the chain ends to prevent loss of the macrocycles via dethreading. Polyrotaxanes show unique behavior in terms of solubility, solid state structure and phase transitions. In this research, fundamental understanding of the threading of cyclic molecules by linear species is sought with respect to factors such as the nature of the two components (size, rigidity, structural similarity), the solvent (conformational aspects of the two components) and temperature. Entirely new polyrotaxanes of several types will be synthesized. Rotaxanes derived from polymeric macrocycles, both backbone and pendant, will be utilized in blend compatibilization and viscosity enhancement. Dendrimers with rotaxane surfaces will allow tailoring of the shape and surface functionality of these versatile entities. Self-assembly will be utilized in two ways: 1) to generate copolymers of block and graft types through complexation and rotaxane formation and 2 use of the physical functionality associated with the cyclic and linear components in the preparation of novel "slip link" macromolecules, which are expected to be uniquely compliant in both tension and compression. Results from this research will span the range from basic understanding, practical application to manipulate properties of known backbones, and preparation of entirely new types of structures. ***
