Robert B. (Barney) Grubbs, Associate Professor
Joint with Brookhaven National Laboratory
Scientist, Center for Functional Nanomaterials, Brookhaven National Laboratory
B.A. Pomona College, (1993)
M.S. Cornell University (w/ J. Fréchet), 1995
Ph.D. Cornell University (w/ J. Fréchet, 1998
Postdoctoral research at the University of Minnesota (w/ F. Bates)
Phone: (631) 632-7911
My research group is interested in the common ground shared by polymer, organic, and materials chemistry and we are involved in the design, synthesis, and characterization of polymer-based organic materials. Polymer physics provides a framework for understanding the basics of copolymer self-assembly in the bulk and in solution and this knowledge, in turn, suggests concepts for the design of novel polymers and copolymers that will organize into predictable arrangements on the nanometer scale. Such assemblies, many inspired by biological systems, are predicted to exhibit novel properties in a range of possible applications.
The combination of living anionic, free radical, and cationic polymerization methods can provide access to many possible polymeric structures, and many techniques of organic chemistry are applicable to the modification of these polymers for the preparation of an even larger variety of materials. We use these techniques to realize specifically designed polymeric architectures. Synthesis of these materials is the major focus of the research program, and students will gain experience in many synthetic techniques. A number of techniques for characterization of new materials by established methods (i.e., small-angle scattering, electron microscopy, etc.) at both the molecular level and at longer length scales are also used.
Representative research projects being undertaken are outlined below. Each primarily involves the use of living/controlled free radical polymerization techniques in combination with initiator and/or monomer synthesis for the creation of novel polymers that should exhibit interesting self-assembly behavior in solution and in bulk.
Stimulus-Induced Morphological Transformation of Ternary Copolymer Micelles
The micellar form which amphiphilic block copolymers adopt in water is strongly governed by the relative volumes of the hydrophobic and hydrophilic blocks. The preparation of triblock copolymers with the hydrophilic and hydrophobic end blocks typical of amphiphilic block copolymers, but with a central block which exhibits condition-dependent water-solubility, will be targeted. Adjustment of the hydrophilic-hydrophobic balance in these polymeric systems should lead to interesting stimulus-induced changes in micellar form, which will be studied by techniques such as light scattering and small-angle x-ray scattering.
Incorporation of Metallic Nanoparticles into Polymeric Matrices
In collaboration with Dave Glueck at Dartmouth, multiblock copolymers wherein different blocks and utilized to specifically stabilize the formation of ordered arrays of nanoparticles composed of different metals are being prepared. Related polymers are being explored with collaborators at Brookhaven National Laboratory.
New Alkoxyamines for Controlled Free Radical Polymerization
We are investigating the preparation of new alkoxyamines by reaction of nitrosoalkanes with carbon-centered radicals as outlined below. New functional alkoxyamines are being designed for the preparation of end-functional polymers.
This material is based upon work supported by the National Science Foundation under Grants DMR-0239697 and DMR-0804792. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).
Nam, C.-Y.; Qin, Y.; Park, Y. S.; Hliang, H.; Lu, X.; Ocko, B. M.; Black, C. T. Grubbs, R. B. “Photocrosslinkable azide-functionalized polythiophene for thermally stable bulk heterojunction solar cells.” Macromolecules 2012, 45, 2338-2347. (link)
Grubbs, R. B. “Nitroxide-Mediated Radical Polymerization: Limitations and Versatility.” Polym. Rev. 2011, 51, 104-137. (link)
Cai, Y.; Aubrecht, K. B.; Grubbs, R. B. “Thermally-induced Changes in Amphiphilicity Drive Reversible Restructuring of Assemblies of ABC Triblock Copolymers with Statistical Polyether Blocks.” J. Am. Chem. Soc. 2011, 133, 1058-1065. (link)
Greene, A.; Grubbs, R. B. “Synthesis and Evaluation of an Ester-Functional Alkoxyamine and Corresponding Nitroxide-Fidelity Studies.” J. Polym. Sci., Part A: Polym. Chem 2009, 47, 6342-6352. (link)
Greene, A.; Grubbs, R. B. “Synthesis and Evaluation of N-Phenylalkoxyamines for Nitroxide-Mediated Polymerization.” Macromolecules 2009, 42, 4388-4390. (link)
Greene, A.; Grubbs, R. B. “Current Methods for N-Alkoxyamine Synthesis.” ACS Symposia 2009, 1024 (Controlled/Living Radical Polymerization: Progress in RAFT, DT, NMP & OMRP), 81-93. (link)
Sundararaman, A.; Stephan, T.; Grubbs, R. B. “Reversible Restructuring of Aqueous Block Copolymer Assemblies through Stimulus-Induced Changes in Amphiphilicity.” J. Am. Chem. Soc. 2008, 130, 12264-12265. (link)
Grubbs, R. B. “Roles of Polymer Ligands in Nanoparticle Stabilization.” Polym. Rev. 2007, 47, 197-215. (link)
Sessions, L. B.; Cohen, B. R.; Grubbs, R. B. “Alkyne-Functional Polymers through Sonogashira Coupling to Poly(4-Bromostyrene).” Macromolecules 2007, 40, 1926-1933. (link)
Xia, Q.; Grubbs, R. B. “In Situ Generation of Nitroxide from Alkoxyamines for Controlled Acrylate Polymerization.” J. Polym. Sci., Part A: Polym. Chem. 2006, 44, 5128-5136. (link)
Aubrecht, K. B.; Grubbs, R. B. "Synthesis and Characterization of Thermoresponsive Amphiphilic Block Copolymers Incorporating a Poly(Ethylene oxide-stat-Propylene oxide) Block." J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 5156-5167. (link)
Grubbs, R. B. "Hybrid Metal-Polymer Composites from Functional Block Copolymers." J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 4323-4336. (link)
Wegrzyn, J. K.; Stephan, T.; Lau, R. N.; Grubbs, R. B. "Preparation of poly(ethylene oxide)-block-polyisoprene by nitroxide-mediated free radical polymerization from PEO macroinitiators." J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 2977-2984.(link)
Sessions, L. B.; Mîinea, L. A.; Ericson, K. D.; Glueck, D. S.; Grubbs, R. B. "Alkyne-functional Homopolymers and Block Copolymers through Nitroxide-Mediated Free Radical Polymerization of 4-(Phenylethynyl)styrene." Macromolecules 2005, 38, 2116-2121. (link)
Grubbs, R. B.; Wegrzyn, J. K.; Xia, Q. "One-step synthesis of alkoxyamines for nitroxide-mediated radical polymerization." Chem. Comm. 2005, 80-82. (link)
Mîinea, L. A.; Sessions, L. B.; Ericson, K. D.; Glueck, D. S.; Grubbs, R. B. "Phenylethynylstyrene-Cobalt Carbonyl Block Copolymer Composites." Macromolecules 2004, 37, 8967-8972. (link)