PMSE 97 |
| Linear-dendritic hybrid copolymers offer a clear opportunity to take advantage of the properties of dendrimers and the phase segregated morphological self-assembly of traditional block copolymers, which have been shown to self-assemble in solution to form concentrated lyotropic phases such as lamellae and columnar phases, and micellar phases consisting of spherical and cylindrical micellar systems. Of particular interest to our group is the solution assembly behavior of amphiphilic and charged linear dendritic block copolymers, and their applications. Lamellar and vesicular phases of interest are observed for these materials systems, and the architectural effect of the dendritic hydrophilic head group in the assembly of these structures greatly influence micelle size, shape, and structure, often correlating well with the predictive behavior of the Israelachvili model for amphiphilic molecular assembly. Comparisons in the solution assembly behavior of the hybrid copolymers in which the linear block backbone is varied from flexible low Tg polypropylene oxide linear blocks, flexible but high Tg polystyrene linear blocks, and rigid hydrophobized linear poly(n-carboxy anhydride) based polypeptide blocks (PALG) will be addressed. Notably, these systems tend to exhibit different types of phases, ranging from spherical and cylindrical micelles to vesicles based on the backbone flexibility as well as the relative hydrophobicity of the block. In particular, the PALG based rod-dendritic systems exhibit rare faceted vesicular structures, including hexagonal and/or cubic vesicles, when co-assembled with common lipids. This unique assembly behavior, including that of each of the linear-dendritic block copolymers described above will be addressed, as well as current studies toward the use of these stable vesicles and micelles that are of interest in the area of drug delivery and nanoencapsulation. |
|
Block Copolymers as Nanoscale Materials
8:00 AM-11:20 AM, Monday, 11 September 2006 San Francisco Marriott -- Salon 7, Oral
Division of Polymeric Materials: Science & Engineering |