Polymers Main Page > Staff
Directory > Detail..Vijay R. Tirumala , Ph. D. |
|
|
|||
Chemical EngineerElectronics Materials |
|||||
|
Phone:
|
(301) 975-6840
|
||||
|
Fax:
|
(301) 975-3928
|
||||
|
Email:
|
|||||
|
Mail:
|
8541
|
||||
Research InterestsMy interests are in establishing the structure-property-performance relationships which define the applicability of novel soft matter and complex fluid systems. Examples include block copolymers, hydrogels, elastomers, nanofluids, etc. A number of characterization tools are needed to characterize complex soft matter systems. My research predominantly uses scattering methods based on x-rays, neutrons, or light. Current ProjectsSuperior toughness of double-network hydrogels (Mentor: Dr. Wen-li Wu)Addition of a high molecular weight linear polymer increases the toughness of hydrogels by orders of magnitude while retaining water at 90% by volume. In this collaborative study between NIST and Hokkaido University (Japan), I mentored and helped a graduate student from Hokkaido to relate the supreme mechanical properties of double-network hydrogels with their microstructure. Characterization methods: SANS, USANS, Neutron Spin-echo, rheology, and optical microscopy. Phase behavior of block copolymer surfactants and their blends with small-molecule additives (Mentors: Prof. Jim Watkins and Dr. Eric Lin) Addition of homopolymer additives that can selectively hydrogen bond improve the segregation strength of polyoxyolefin-based block copolymer surfactants. Highly ordered self-assembled templates of surfactants commercially used in detergent, pharmaceutical, and cosmetic industry are useful in the inexpensive fabrication of nanomaterials. In our study, the ordered templates are used to prepare mesoporous silica films for low-k applications. Characterization Methods: SAXS, x-ray reflectivity, SANS. Selected Publications- V.R. Tirumala, C.M. Stafford, R. Huang, L.E. Ocola, "Swelling behavior of supported polymer nanolines", in preparation.- V.R. Tirumala, V. Daga, A.W. Bosse, A. Romang, J. Ilavsky, E.K. Lin, J.J. Watkins, "Disorder-to-Order transition in Low Molar Mass Pluronic Copolymer Melts Induced by a Selectively Associating Homopolymer: Effect of Homopolymer Molar Mass", Macromolecules 2008 (submitted). - V.R. Tirumala, T. Tominaga, S. Lee, E.K. Lin, H. Furukawa, J.P. Gong, Y. Osada, W.-L. Wu, "A Molecular Model for Toughening in Double-Network Hydrogels", J. Phys. Chem. B 2008, in press - V.R. Tirumala, A.H. Romang, S. Agarwal, E.K. Lin, J.J. Watkins, Well-ordered block copolymer melts from blends of disordered triblock copolymer surfactants with strongly associating homopolymers, Advanced Materials 2008, DOI: 10.1002/adma.200701577. - T. Tominaga, V.R. Tirumala, S. Lee, E.K. Lin, J.P. Gong, H. Furukawa, Y. Osada, W. Wu, Thermodynamic Interactions in Double-Network Hydrogels, J. Phys. Chem. B, 2008, 112, 3903-3909. - T. Tominaga, V.R. Tirumala, J.P. Gong, H. Furukawa, Y. Osada, E.K. Lin, W. Wu, The Molecular Origin of Enhanced Toughness in Double-Network Hydrogels: A Neutron Scattering Study, Polymer 2007, 48, 7449-7454. - V.R. Tirumala, R.A. Pai, S. Agarwal, C. Chandler, G. Bhatnagar, A. Romang, R. Jones, E.K. Lin, J.J. Watkins, Enhanced long-range order in mesoporous silicate films prepared from amphiphilic block copolymer/homopolymer blends with selective hydrogen bonding, Chem. Mater. 2007, 19, 5868-5874. - V.R. Tirumala, J. Ilavsky, and M. Ilavsky, Effect of monomer structure and ionic comonomer concentration on the coil-to-globule transition of n-alkyl(meth)acrylamide hydrogels, J. Chem. Phys. 2006, 124, 234911. - V.R. Tirumala, R. Divan, L.E. Ocola, D.C. Mancini, Direct-write e-beam patterning of stimuli-responsive hydrogels, J. Vac. Sci. Tech. B 2005, 23(6),3124-3128. - V.R. Tirumala, D.C. Mancini, and G.T. Caneba, Synthesis of Ultrafast Response Smart Microgel Structures, Proc. SPIE 2004, 5389, 221. Invited Presentations- Why are Double-Network Hydrogels Tough?, Small-angle Scattering Workshop, Advanced Photon Source User's Meeting (May 4-8, 2008)- Neutron Scattering Studies of Double-Network Hydrogels, ACS Colloids & Surface Science Symposium, Delaware DE (June 24-27 2007). - Responsive Hydrogels as Model Materials to Study the Deformation Behavior of Patterned Polymer Nanostructures, NSTI Nanotech, Santa Clara CA (May 23 2007). - Characterization of poly (N-isopropylacrylamide) hydrogels by ultra-small-angle neutron scattering, presented at the American Crystallography Association, Chicago IL (July 21 2004). - Controlling polymer chain growth: A new paradigm, Advanced Photon Source User Science Seminar, Argonne IL (January 16 2004). - Synthesis of nanostructured polymers from lithography and self-Assembly, poster presented at the DOE Nanoscale Science Research Centers Workshop, Washington DC (Feb. 26-28 2003). Patents and Invention Disclosures- G. T. Caneba, V. R. Tirumala, D.C. Mancini, and H.H. Wang, Spatially controlled, in situ synthesis of polymers, United States Patent No. 6,869,983.- V.R. Tirumala, R. Divan, L.E. Ocola, D.C. Mancini, Fabrication of stimuli-responsive polymeric nanostructures, invention reported to Argonne National Laboratory, ANL-IN-05-061, May 2005. |
|||||
| NIST Materials Science & Engineering Laboratory - Polymers Division | |||||
