Department of Materials Science and Engineering

Christopher Kemper Ober is the Francis Bard Professor of Materials Engineering at Cornell University. After several years in industry at the Xerox Research Centre of Canada, Ober moved to Cornell as an Assistant Professor in 1986. His research is focused on lithography, patterning, the biology materials interface and control of surface structure in thin films. As a reflection of his contributions to lithography, Ober received the 2003 International Sematech Outstanding Contribution Award and in 2004 was honored with the Photopolymer Science & Technology Award. An Associate Editor of Macromolecules and the President of the IUPAC Polymer Division, he is the 2006 winner of the American Chemical Society Award in Applied Polymer Science and received a Humboldt Research Prize in 2007. In 2007, he chaired the NSF Polymers Workshop. Ober recently became Associate Dean of Research and Graduate Studies.

The ability to tailor the chemical structure of materials provides the ability to exquisitely control materials properties. Polymers, more than any other material, offer this possibility to fine-tune their thermal, optical and electrical properties. Polymers are also the basis of the nanotechnology revolution, serving as photoresists used to create nanometer scale structures. Our research is therefore focused in three areas: fundamental studies of self-organization in polymers, lithographic materials for microelectronics and biotechnology and new environmentally and biologically friendly materials. Each of these topics involves creative polymer synthesis using both state-of-the-art facilities and methods as well as advanced characterization tools, many of which are located here at Cornell University. The research group, consisting of a mixture of graduate students and post-doctoral associates, takes part in highly collaborative research with leading groups at Cornell and around the world.

• Biology-materials interface: the blood brain barrier; cell-surface interactions (NBTC)
• Environmentally friendly, fouling resistant surfaces (ONR, SERDP)
• Supercritical CO2 processing of photoresists (SRC, Intel)
• Polymer brushes and interface engineering (NSF)
• Molecular glass photoresists for high resolution, next generation lithography (SRC)
• Flexible electronics for biological applications (NYSTAR, NSF)
• Hydrogels as mechanical buffers and drug delivery agents for neural electronics (NIH)
• Hybrid polymers for photonic materials (CCMR)
• Top down/Bottom up lithography using photopatternable block copolymers (IBM, SRC)

• Jin-Kyun Lee, Margarita Chatzichristidi, Alexander Zakhidov, Priscilla G. Taylor, John A. DeFranco, Ha Soo Hwang, Hon Hang Fong, Andrew B. Holmes, George G. Malliaras, Christopher K. Ober, “Acid-sensitive Semi-perfluoroalkyl Resorcinarene: An Imaging Material for Organic Electronics”, JACS, in press.
• Anuja De Silva, Nelson M. Felix, and Christopher K. Ober, “Molecular Glass Resists as High Resolution Patterning Materials”, Adv. Mater., in press.
• J. K. Bosworth, M. Y. Paik, R. Ruiz, E. L. Schwartz, J. Q. Huang, A. W. Ko, D.-M. Smilgies, C. T. Black and C. K. Ober, “Control of Self Assembly of Lithographically-Patternable Block Copolymer Films”, ACS Nano, in press.
• Sitaraman Krishnan, Craig J. Weinman and Christopher K. Ober, “Advances in Polymers for Anti-Biofouling Surfaces”, J. Mater. Chem., in press.
• A. A. Zakhidov, Jin-Kyun Lee, Hon Hang Fong, John A. DeFranco, Margarita Chatzichristidi, Priscilla Taylor, Christopher K. Ober and George G. Malliaras, “Orthogonal solvents for chemical processing of organic electronic materials”, Adv. Mater., in press.
• Nelson Felix and Christopher K. Ober, “Acid-Labile, Chain-Scission Polymer Systems Used as Positive-Tone Photoresists Developable in Supercritical CO2”, Chem. Mater., in press.
• Ha Soo Hwang, Alexander A. Zakhidov, Jin-kyun Lee, Xavier André, John A. DeFranco, Hon Hang Fong, Andrew B. Holmes, George G. Malliaras, Christopher K. Ober, “Dry Photolithographic Patterning Process for Organic Electronic Devices using Supercritical Carbon Dioxide as a Solvent”, J. Mater. Chem., 2008, 18, 3087 - 3090.
• Nelson M. Felix, Anuja De Silva, and Christopher K. Ober, “Calix[4]resorcinarene Derivatives as High Resolution Photoresist Materials for Supercritical CO2 Processing”, Adv. Mater., (2008), 20(7), 1303-1309.
• Ji-Hyun Jang, Shalin J. Jhaveri, Boris Rasin, Choeng Yang Koh, Christopher K. Ober and Edwin L. Thomas, “Three-dimensionally Patterned Submicron Scale Hydrogel/Air Networks that Offer a New Platform for Biomedical Applications”, Nano Letters, in press.
• Zimmerman, Paul A.; Byers, Jeffrey; Rice, Bryan; Ober, Christopher K.; Giannelis, Emmannuel P.; Rodriguez, Robert; Wang, Dongyan; O’Connor, Naphtali; Lei, Xuegong; Turro, Nicholas J.; Liberman, Vladimir; Palmacci, Stephen; Rothschild, Mordechai; Lafferty, Neal; Smith, Bruce W.  Development and evaluation of a 193nm immersion generation-three fluid candidates.   Proceedings of SPIE (2008), 6923 69230A-69230A-10.
• Zimmerman, Paul A.; Byers, Jeffrey; Piscani, Emil; Rice, Bryan; Ober, Christopher K.; Giannelis, Emmannuel P.; Rodriguez, Robert; Wang, Dongyan; Whittaker, Andrew; Blakey, Idriss; Chen, Lan; Dargaville, Bronwin; Liu, Heping.  Development of an operational high refractive index resist for 193nm immersion lithography.   Proceedings of SPIE (2008), 6923 692306-692306-10.
• Yi, Yi; Ayothi, Ramakrishnan; Ober, Christopher K.; Yueh, Wang; Cao, Heidi.  Ionic photoacid generators containing functionalized semifluorinated sulfonates for high-resolution lithography.   Proceedings of SPIE (2008), 6923 69231B-69231B-8.
• Kang, Shuhui; Lavery, Kristopher; Choi, Kwang-Woo; Prabhu, Vivek M.; Wu, Wen-Li; Lin, Eric; De Silva, Anuja; Felix, Nelson; Ober, Christopher.  A comparison of the reaction-diffusion kinetics between model-EUV polymer and molecular-glass photoresists.   Proceedings of SPIE (2008), 6923 692317-692317-12. CODEN: PSISDG ISSN:0277-786X.
• VanderHart, David L.; De Silva, Anuja; Felix, Nelson M.; Prabhu, Vivek M.; Ober, Christopher K..  The effect of EUV molecular glass architecture on the bulk dispersion of a photo-acid generator.   Proceedings of SPIE (2008), 6923 69231M-69231M-15.
• De Silva, Anuja; Felix, Nelson; Sha, Jing; Lee, Jin-Kyun; Ober, Christopher K..  Molecular glass resists for next generation lithography.   Proceedings of SPIE (2008), 6923 69231L-69231L-14. CODEN: PSISDG ISSN:0277-786X.
• Felix, Nelson M.; De Silva, Anuja; Sha, Jing; Ober, Christopher K..  Achieving small dimensions with an environmentally friendly solvent: photoresist development using supercritical CO2.   Proceedings of SPIE (2008), 6923 69233L-69233L-11. 
• Anuja De Silva and Christopher K. Ober, “Hydroxyphenylbenzene Derivatives as Glass Forming Molecules for High Resolution Photoresists”, J. Mater. Chem., 2008, 18, 1903 - 1910.
• Anuja De Silva, Jin Kyun Lee, Xavier André, Nelson M. Felix, Heidi B. Cao, Hai Deng and Christopher K. Ober, “Study of the Structure-Properties Relationship of Phenolic Molecular Glass Resists for Next Generation Photolithography”, Chem. Mater., 20 (4), 1606–1613, 2008.
• Nagarajan, Sivakumar; Bosworth, Joan; Ober, Christopher; Russell, Thomas; Watkins, James, “Simple Fabrication of Micropatterned Mesoporous Silica Films Using PAGs in Block Copolymers”, Chem. Mater., 20(3) 604-606, 2008.
• Sivakumar Nagarajan, Rajaram A. Pai, Thomas P. Russell, James J. Watkins, Mingqi Li, Katy S. Bosworth, Detlef-M. Smilgies, Christopher K. Ober, “An Efficient Route to Mesoporous Silica Films with Perpendicular Nanochannels”, Adv. Mater., 2008, 20(2), 246–251.
• John A Finlay, Sitaraman Krishnan, Maureen E Callow, James A Callow, Rong Dong, Nicola Asgill, Kaiming Wong, Edward J. Kramer, Christopher K. Ober, “Settlement of Ulva Zoospores on Patterned Fluorinated and PEGylated Monolayer Surfaces”, Langmuir, (2008), 24(2), 503-510.
• Frauke Pfeiffer, Nelson M. Felix, Christian Neuber, Christopher K. Ober, and Hans-Werner Schmidt, “Towards Environmentally Friendly, Dry Deposited, Water Developable Molecular Glass Photoresists”, Physical Chemistry Chemical Physics, 10(9), 1257-1262: 2008.
• Nelson M. Felix, Anuja De Silva, Camille Man Yin Luk and Christopher K. Ober, “Dissolution Phenomena of Phenolic Molecular Glass Photoresist Films in Supercritical CO2”, J. Mater. Chem., (2007), 17(43), 4598-4604.
• Joan K. Bosworth, Xavier Andre, Evan L. Schwartz, Ricardo Ruiz, Charles T. Black and Christopher K. Ober, "Control of Morphology Orientation in Lithographically Patternable Diblock Copolymers", Journal of Photopolymer Science and Technology, (2007), 20(4), 519-522.
• Rong Dong, Sitaraman Krishnan, Barbara A. Baird, Manfred Lindau, Christopher K. Ober*, “Patterned Biofunctional Polymer Brushes”, Biomacromolecules, (2007), 8(10), 3082-3092.
• Xavier André, Jin Kyun Lee, Anuja DeSilva, Christopher K. Ober, Heidi B. Cao, Hai Deng, Hiroto Kudo, Daisuke Watanabe, Tadatomi Nishikubo, "Phenolic Molecular Glasses as Resists for Next Generation Lithography", Proceedings of SPIE-The International Society for Optical Engineering (2007), 6519(Pt. 2, Advances in Resist Materials and Processing Technology XXIV), 65194B/1-65194B/10.
• Frauke Pfeiffer, Nelson Felix, Christian Neuber, Christopher K. Ober, Hans-Werner Schmidt, “Physical Vapor Deposition of Chemically Amplified Photoresists: A New Route to Patterning Molecular Glass Resists”, Advanced Functional Materials (2007), 17(14), 2336-2342.
• Niamsiri, Nuttawee; Bergkvist, Magnus; Delamarre, Soazig C.; Cady, Nathan C.; Coates, Geoffrey W.; Ober, Christopher K.; Batt, Carl A. Insight in the role of bovine serum albumin for promoting the in situ surface growth of polyhydroxybutyrate (PHB) on patterned surfaces via enzymatic surface-initiated polymerization. Colloids and Surfaces, B: Biointerfaces (2007), 60(1), 68-79.
• Daniel Bratton, Ramakrishnan Ayothi, Hai Deng, Heidi B. Cao and Christopher K. Ober, “Diazonaphthoquinone Molecular Glass Photoresists: Patterning without Chemical Amplification ”, Chem. Mater., 19(15); 3780-3786 (2007).
• Birger Lange, Shalin J. Jhaveri, Lorenz Steidl, R. Ayothi and Christopher K. Ober, Rudolf Zentel, "Creating defined 3D defects inside an opaline Ormocer® matrix with two-photon lithography”, Macromol. Rapid Commun., 2007, 28, 922–926.
• Marvin Y. Paik, Sitaraman Krishnan, Fengxiang You, Xuefa Li, Yushi Ando, Seok Ho Kang, Alexander Hexemer, Edward J. Kramer, Daniel A. Fischer, Christopher K. Ober, “Surface organization, light-driven surface changes and stability of semifluorinated azobenzene polymers”, Langmuir, 2007, 23, 5110-5119.
• R. Ayothi, Y. Yi, H. Cao, Y. Wang, S. Putna, C. K. Ober, “Arylonium photoacid generators containing environmentally compatible aryloxyperfluoroalkanesulfonate groups”, Chem. Mater., 19(6): 1434-1444 (2007).
• Peter Busch, Sitaraman Krishnan, Marvin Paik, Gilman E.S. Toombes, Detlef-M. Smilgies, Sol M. Gruner and Christopher K. Ober, “Surface induced tilt propagation in thin films of semifluorinated liquid-crystalline side-chain block copolymers”, Macromolecules, 40(1): 81-89 (2007).
• Daniel Bratton, Ramakrishnan Ayothi, Nelson Felix and Christopher K. Ober, “Applications of Controlled Macromolecular Architectures to Lithography”, in Macromolecular Engineering: From Precise Macromolecular Synthesis to Macroscopic Materials Properties and Application, K. Matykaszewski, Y. Gnanou and L. Leibler, eds., Wiley-VCH, Weinheim, 2007.
• Mingqi Li, Christopher K. Ober, “High Resolution Patterning with Block Copolymers”, Materials Today, Volume 9, Issue 9, September 2006, Pages 30-39.
• Sitaraman Krishnan, Rebekah J. Ward, Alexander Hexemer, Kristen L. Lee, Esther R. Angert, Daniel A. Fischer, Edward J. Kramer, Christopher K. Ober, “Surfaces of Fluorinated Pyridinium Block-Copolymers with Enhanced Antibacterial Activity”, Langmuir, 22 (26): 11255-11266 (2006).
• Young-Je Kwark, J. Pablo Bravo, Manish Chandhok, Heidi Cao, Hai Deng and Christopher K. Ober, “Absorbance Measurement of Polymers at EUV Wavelength: Correlation between experimental and theoretical calculations”, JVSTB, B 24 (4): 1822-1826 JUL-AUG 2006.
• Fengxiang You, Marvin Y. Paik, Michael Häckel, Lothar Kador, Daniela Kropp, Hans-Werner Schmidt, Christopher K. Ober, “Suppressing Surface Relief Gratings in Liquid Crystalline Perfluoralkyl-azobenzene Polymers”, Adv. Func. Mater., 16 (12): 1577-1581 AUG 4 2006.
• Junyan Dai, Seung Wook Chang, Alyssandrea Hamad, Da Yang, Nelson Felix, Christopher K. Ober, “Molecular Glass Resists For High Resolution Patterning”, Chem. Mater., 18(15): 3404-3411 2006.
• Wageesha Senaratne, Kazutake Takada, Raibatak Das, Jamie Cohen, Héctor D. Abruña, Barbara Baird and Christopher K. Ober, “Dinitrophenyl Ligand Substrates and their Application to Immunosensors”, Biosensors and Bioelectronics, 2006, Vol 22/1 pp 63-70
• J. Y. Mao, N. Felix, P. Nguyen, C. K. Ober and K. K. Gleason, “Positive and Negative Tone Chemical Vapor Deposited Polyacrylic E-beam Resists Developable by Supercritical CO2”, Advanced Materials, Chem. Vap. Deposition 2006, 12, 259–262.
• Ramakrishnan Ayothi, Yi Yi, Christopher K Ober, Steve Putna, Wang Yueh and Heidi Cao, “All-organic Non-PFOS Nonionic Photoacid Generating Compounds with Functionalized Fluoroorganic Sulfonate Motif for Chemically Amplified Resists”, Proceedings of SPIE-The International Society for Optical Engineering (2006), 6153 -61530J.
• Daniel Bratton, Ramakrishnan Ayothi, Nelson Felix, Heidi Cao, Hai Deng, Christopher K. Ober, “Molecular Glass Resists for Next Generation Lithography”, Proceedings of SPIE-The International Society for Optical Engineering (2006), 6153 61531D.
• Nelson Felix, Kousuke Tsuchiya, Camille Man Yin Luk and Christopher K. Ober, “Supercritical CO2 for High Resolution Photoresist Development”, Proceedings of SPIE-The International Society for Optical Engineering (2006), 6153 61534B.
• Shinji Tanaka, Christopher K Ober, “Adamantane Based Molecular Glass Resists for 193nm Lithography”, Proceedings of SPIE-The International Society for Optical Engineering (2006), 6153 - 61532B.
• Anuja De Silva, Drew Forman, Christopher K. Ober, “Molecular Glass Resists for EUV Lithography”, Proceedings of SPIE-The International Society for Optical Engineering (2006), 6153 615341.
• Sitaraman Krishnan, Ramakrishnan Ayothi, Alexander Hexemer, John Finlay, Karen Sohn, Ruth Perry, Christopher K. Ober, Edward J. Kramer, Maureen E. Callow, James A. Callow, Daniel Fischer, “Anti-Biofouling Properties of Comb-Like Block Copolymer with Amphiphilic Side-Chains”, Langmuir, (2006), 22(11), 5075-5086.
• Sitaraman Krishnan, Nick Wang, Christopher K. Ober,* John Finlay, Maureen E. Callow, James A. Callow, Alexander Hexemer, Edward J. Kramer, Daniel A. Fischer, “Comparison of the Fouling Release Properties of Hydrophobic Fluorinated and Hydrophilic PEGylated Block Copolymer Surfaces: Attachment Strength of the Diatom Navicula and the Green Alga Ulva”, Biomacromolecules, (2006), 7(5), 1449-1462.
• Osuji, Chinedum O.; Chao, Chi-Yang; Ober, Christopher K.; Thomas, Edwin L. “Supramolecular Microphase Separation in a Hydrogen-Bonded Liquid Crystalline Comb Copolymer in the Melt State”, Macromolecules, (2006), 39(9), 3114-3117.
• Wageesha Senaratne, Prabuddha Sengupta, Vladimir Jakubek, David Holowka, Christopher K. Ober and Barbara Baird, “Self-assembled monolayer functionalized surface arrays for investigating immune cell signaling”, JACS, (2006), 128(17), 5594-5595.
• Seung Wook Chang, Ramakrishnan Ayothi, Daniel Bratton, Da Yang, Nelson Felix, Heidi B. Cao, Hai Deng and Christopher K. Ober, “Sub 50 nm Feature Sizes using Positive Tone Molecular Glass Resists for EUV Lithography”, J. Mater. Chem., 2006, 16, 1470.
• Daniel Bratton, Da Yang, Junyan Dai and Christopher K. Ober, “Recent progress in high resolution lithography”, Polymers for Advanced Technology, 2006: 17: 94-103.
• Nelson M. Felix, Kosuke Tsuchiya, and Christopher K. Ober, “High-Resolution Patterning Using Molecular Glasses and Supercritical Carbon Dioxide”, Adv. Mater., (2006), 18(4), 442-446.
• Da Yang, Seung Wook Chang, Christopher K. Ober, “Molecular Glass Photoresists for Advanced Lithography”, J. Mater. Chem., 2006, 16, 1693 - 1696.
• Kim, Young-Rok; Paik, Hyun-Jong; Ober, Christopher K.; Coates, Geoffrey W.; Mark, Sonny S.; Ryan, Thomas E.; Batt, Carl A. Real-time analysis of enzymatic surface-initiated polymerization using surface plasmon resonance (SPR). Macromolecular Bioscience (2006), 6(2), 145-152.

• Associate Dean for Research and Graduate Studies (9/07 to present),Cornell University, Ithaca, NY 14853
• 2008 NSF Special Creativity AwardPresident, IUPAC Polymer Division
• 2007 Humboldt Research Prize
• 2006 ACS Award in Applied Polymer Science
• Francis Norwood Bard Professor of Materials Engineering (1/01 to present), Department of Materials Science & Engineering, Bard Hall, Cornell University, Ithaca, NY 14853
• Director (1/00 to 12/03) Department of Materials Science & Engineering, Bard Hall, Cornell University, Ithaca, NY 14853
• Professor, (7/98 - present) Department of Materials Science & Engineering, Bard Hall, Cornell University, Ithaca, NY 14853
• Associate Professor, (7/92 - 6/98) Department of Materials Science & Engineering, Bard Hall, Cornell University, Ithaca, NY 14853
• Director of Graduate Studies (1/91 - 12/94), Department of Materials Science & Engineering, Bard Hall, Cornell University, Ithaca, NY 14853
• Assistant Professor, (9/86 - 6/92) Department of Materials Science & Engineering, Bard Hall, Cornell University, Ithaca, NY 14853
• Senior Member of Research Staff, (9/84 - 8/86) Xerox Research Centre of Canada, Mississauga, ON, Canada.
• NSERC Canada Industrial Postdoctoral Fellow, (4/82 - 8/84) Xerox Research Centre of Canada, Mississauga, ON, Canada.

Education

• Ph.D., 1982. Department of Polymer Science & Engineering, University of Massachusetts, Amherst, MA
• NSERC Canada Graduate Fellow, 1978-1982
• Thesis: “The Synthesis and Characterization of Liquid Crystalline Polyesters Based upon p-Hydroxybenzoic Acid” under the guidance of Prof. R. W. Lenz
• M.S., 1980. Department of Polymer Science & Engineering, University of Massachusetts, Amherst, MA
• B.Sc., 1978. University of Waterloo, Waterloo, Ontario, Canada
• Major: Honours Chemistry (Co-Operative Programme)
• Chem 13 Scholar 1973-1978