9708581 Percec This research will design libraries of monodendritic building blocks with well defined flat tapered and conical shapes which self-assemble into cylindrical and respectively spherical shapes. These supermolecules will generate columnar hexagonal and spherical thermotropic and lyotropic liquid crystalline (LC) phases. These LC phases will warrant a thermodynamic control of their assembly and will allow the determination of their shape by X-ray diffraction. Libraries of flat tapered and conical monodendritic building blocks functionalized with polymerizable groups will be polymerized via living methods to generate the first examples of giant polymers with cylindrical and spherical shapes with diameter and length and respectively diameter controlled at the nanoscale level. The organization of these giant dendritic monomers in a LC assembly will also be used to aggregate their polymerizable groups in a reactor of artificially enhanced concentration and restricted geometry during the polymerization process and therefore, will generate a new approach to the control of polymerization. This research will provide an entry into the design of polymeric materials with predictable and dramatically different properties which are determined by their shape. Cylindrical and spherical giant polymers obtained from flexible backbones jacketed with dendritic coats will access new mechanisms to control the conformation and rigidity of their flexible chain regardless of their tacticity. Mechanisms to change in a reversible and controlled way the shape of the polymer from rod-like to spherical will be elaborated. It is expected that these cylindrical 3-D polymers will produce more rigid structures than the currently known 1-D linear rigid-rods. %%% This research will transplant concepts from Nature into the field of complex synthetic polymeric materials. Natural systems provide the most efficient mechanisms for the storage and transfer of energy and information and for the production of structural materials. The polymeric systems developed by this program will provide new technologic concepts which will allow for the first time the development of new materials such as functional fibers, films, membranes, viscosity controllers, electronic, photonic and controlled release systems with externally regulated physical properties via principles elaborated by Nature during the long process of evolution. ***
