The goal of our research is to understand on a molecular level a broad range ofmacroscopic properties of polymers. Owing to the tremendous diversity of their physical properties, polymeric materials find applications ranging from themost common to the most exotic products in the forms of fibers, plastics, elastomers, adhesives, and coatings. Inevitably, the final properties of thematerial depend not only on the chemical constitution of the polymer, but also on its physical structure or conformation. In our group we explore generalaspects of the latter, relating the macromolecular structure and dynamics tothe macroscopic properties. Present problems of interest include (1) thedynamics of each component in miscible polymer blends, (2) manipulation of thealignment of liquid-crystalline polymers using flow, (3) the disorder-ordertransition of block-copolymers, and (4) controlling molecular order in thinpolymer films.
To obtain information on the desired molecular or microscopic scales, a rangeof techniques and model polymer systems is used. In some problems, it isnecessary to use techniques that probe particular molecules in a multicomponentsystem or of specific parts of molecules in a topologically complex polymer.This is accomplished by using spectroscopic techniques, both infrared andnuclear magnetic resonance, that allow isotopically labeled components to beobserved. In our laboratory, these methods are combined with dynamicmechanical testing, allowing us to measure directly the contribution of eachspecies to the optical anisotropy and stress. To track meso-scale dynamicsthat are important in liquid crystals and ordered block copolymers, we combinemicroscopy, light scattering and rheological measurements.
In some cases it is necessary to develop new experimental techniques to accesscritical information. Toward the goal of producing uniform, highly alignedpolymer films, it is necessary to image the degree and direction of alignmentin such films. Therefore, we have developed a new microscope that integratesrecent advances in laser-scanning microscopy with polarization-modulationpolarimetry. This combination enables us to image molecular orientation withhigh spatial resolution, sensitivity and speed. We are using this uniquecapability to study orientational order in ultrathin Langmuir-Blodgett films ofrodlike polymers.
Arendt, B. H.; Kannan, R. M.; Zewail, M.; Kornfield, J. A.; Smith, S. D. Dynamics of Each Component in Miscible Blends of Polyisoprene and Polyvinylethylene. Rheologica Acta. 1994;
Arendt, B. H.; Krishnamoorti R; Kannan, R. M.; Zewail, M.; Kornfield, J. A. Dynamics of each Component in Miscible Blends of Polyisoprene and Polyvinylethylene. Abstracts of Papers of the American Chemical Society. 1994;
Chen, Z. R.; Claverie, J. P.; Grubbs, R. H.; Kornfield, J. A. Modeling Ring-chain Equilibria in Ring-opening Polymerization of Cycloolefins. Macromolecules. 1995;
Chen, Z. F.; Kornfield, J. A.; Claverie, J. P.; Grubbs, R. A. Ring-chain Equilibria in Ring-opening Metathesis Polymerization (Romp) of Cycloolefins. Abstracts of Papers of the American Chemical Society. 1994;
Chung, G. C.; Kornfield, J. A. (*R; Smith, S. D. Component Dynamics in Miscible Polymer Blends - a 2-Dimensional Deuteron NMR Investigation. Macromolecules. 1994;
Chung, G. C.; Kornfield, J. A. (*R; Smith, S. D. Compositional Dependence of Segmental Dynamics in a Miscible Polymer Blend. Macromolecules. 1994;
Gupta, V. K.; Kornfield, J. A. (*R; Ferencz A; Wegner G. Controlling Molecular Order in Hairy-rod Langmuir-blodgett-films - a Polarization-modulation Microscopy Study. Science. 1994;
Gupta, V. k.; Kornfield, J. A. Polarization Modulation Laser-scanning Microscopy - a Powerful Tool to Image Molecular-orientation and Order. Review of Scientific Instruments. 1994;
Kannan, R. M.; Kornfield, J. A. The 3rd-normal Stress Difference in Entangled Melts - Quantitative Stress-optical Measurements in Oscillatory Shear. Rheologica Acta. 1992;
Kannan, R. M.; Kornfield, J. A.; Smith, S. D. Comparison of the Flow-alignment Behavior of Pep-Pee And Ps-Pi Diblock Copolymers. Abstracts of Papers of the American Chemical Society. 1994;
Kannan, R. M.; Kornfield, J. A. (*R. Evolution of Microstructure and Viscoelasticity During Flow-alignment of a Lamellar Diblock Copolymer. Macromolecules. 1994;
Kannan, R. M.; Kornfield, J. A.; Schwenk, N.; Boeffel, C. Rheology of Side-group Liquid-crystalline Polymers - Effect of Isotropic Nematic Transition and Evidence of Flow-alignment. Macromolecules. 1993;
Kannan, R. M.; Kornfield, J. A.; Schwenk, N.; Boeffel, C. Shear-induced Orientation of Side-group Liquid-crystalline Polymers. Advanced Materials. 1994;
Kannan, R. M.; Kornfield, J. A. Stress-optical Manifestations of Molecular and Microstructural Dynamics in Complex Polymer Melts. Journal of Rheology. 1994;
Kannan, R. M.; Rubin, S. F.; Kornfield, J. A. (*R; Boeffel, C. Dynamics of Flow-induced Alignment of Side-group Liquid-crystalline Polymers. Journal of Rheology. 1994;
Kornfield, J. A. Proceedings of the Boston Symposium On Liquid-crystals. Journal of Rheology. 1994;
Kornfield, J. A.; Chung, G. C. Molecular-origins of the Complex Thermorheological Behavior of Polymer Blends as Revealed by 2d Broadline H-2 NMR. Abstracts of Papers of the American Chemical Society. 1994;
Kornfield, J. A.; Chung, G. C.; Arendt, B. H.; Smith, S. D. Optical and NMR Investigation of Dynamics in Miscible Polymer Blends. Abstracts of Papers of the American Chemical Society. 1993;
Kornfield, J. A.; Kannan, R. M. Dynamics of Microstructural Alignment of Block-copolymers During Shear. Abstracts of Papers of the American Chemical Society. 1993;
Kornfield, J. A.; Kannan, R. M.; Arendt, B. H.; Seitz, K.; Roovers, J. Dynamics of Miscible Blends and Disordered Diblock Copolymers. Abstracts of Papers of the American Chemical Society. 1994;
Kornfield, J. A.; Kannan, R. M.; Smith, S. Flipping the Alignment of Lamellar Diblock Copolymers - Distinctive Behaviors of Pep-Pee And Ps-Pi Diblocks. Abstracts of Papers of the American Chemical Society. 1994;
Kornfield, J. A.; Kannan, R. M.; Smith, S. D. Investigation of Flow-alignment of Block-copolymers Using Rheooptical Methods. Abstracts of Papers of the American Chemical Society. 1994;
Rubin, S. F.; Kannan, R. M.; Kornfield, J. A.; Boeffel, C. Flow-induced Alignment of Nematic and Smectic Side-group Liquid-crystalline Polymers. Abstracts of Papers of the American Chemical Society. 1994;
Rubin, S. F.; Kannan, R. M.; Kornfield, J. A.; Boeffel, C. Linear Viscoelasticity of Side-chain Liquid-crystalline Polymers - Effect of Molecular-weight and Nematic and Smectic Phase-transitions. Abstracts of Papers of the American Chemical Society. 1994;
Smith, S. D.; Noda, I.; Marcott, C.; Dowrey, A. E.; Kornfield, J. A.; Samulski, E. T.; Hutchison, J. The Polymer Interphase - on the Location and Mobility of Selectively Labeled Chain Segments in Block-Copolymers. Abstracts of Papers of the American Chemical Society. 1994;