COLL 436 |
| J. L. Hedrick, IBM Research, Almaden Research Center, 650 Harry Rd, San Jose, CA 95120, Alice P. Gast, Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Rm. 3-240, Cambridge, MA 02139, J. Pople, Stanford Sychrotron Radiation Laboratory, Stanford Linear Accelerator Center, Stanford, CA 94309, Cheryl M. Stancik, Department of Chemical Engineering, Stanford University, Stanford, CA 94305-5025, and Mikael Trollsas, Cohesion Technologies, 2500 Faber place, Palo Alto, CA 94303. |
| Dendritic- or dendrimer-like star polymers are defined as branched materials having generations of high molecular weight polymer between branching junctures emanating from a central core. These materials have comparable mechanical properties to their linear analogs, yet possess many features typical of dendrimers. However, in contrast to dendrimers which require multiple synthetic transformations and associated purification steps to achieve modest molecular weights (~5000 g/mol), molecular weights up to 250 000 g/mol are possible in just a few generations. Dendritic polymers were prepared from the combination of living/controlled polymerization procedures together with quantitative organic transformations using a divergent growth approach. Two general scaffolds for the construction of dendrimer-like star polymers have been surveyed including the first through third generation dendrimers derived from 2,2’-bis(hydroxymethyl)propionic acid as initiators for the ring-opening polymerization of cyclic esters generating six to twenty-four arms, respectively, and linear poly(caprolactone). Considerable flexibility exist, as the generation of the dendrimer initiating core, average molecular weight of the polymer, type of polymer, generation of dendron or functionality of the branching juncture between polymer generations and polymer generation can be varied to obtain complex architectures that resemble the most advanced dendrimers. Moreover, amphiphilic block copolymers in the form of unimolecular micelles have also been demonstrated that have found application as macromolecular templates for the generation of nanoporous organosilicates for microelectronic applications. |
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Symposium in Memory of Arthur W. Adamson
2:00 PM-5:40 PM, Wednesday, March 31, 2004 Marriott -- Orange County 4, Oral
Division of Colloid and Surface Chemistry |