Laboratory for Dynamic NMR

Charles S. Johnson, Jr. - NSF Fellow at MIT, NAS-NRC Postdoctoral Fellow at the University of Illinois, A.P. Sloan and J.S. Guggenheim Fellowships, Fellow of the American Physical Society and the American Association for the Advancement of Science

The research goals of our laboratory are the development and application of novel nuclear magnetic resonance (NMR) methods. There is particular emphasis on NMR applications involving molecular motion and chemical rate processes. In this work analogies between NMR and laser light diffraction are used to aid the design and interpretation of experiments. Two active projects are briefly described below:

Interactions of Surface Active Polymers in Liquid and Supercritical CO₂

This work is motivated by the growing importance of environmentally benign CO₂ as a solvent system for polymerization reactions and in cleaning processes. Diffusion ordered NMR methods are being used to gain an understanding of surfactant self-assembly reactions in CO₂ as well as the transport of residual monomers in CO₂ swollen polymers. Self-assembly will be followed with pulsed field gradient stimulated echo (PFG-STE) type experiments, e.g. bipolar pulse - longitudinal eddy current delay (BPP-LED) experiments, as a function of diffusion time. The aim is to determine the sizes of aggregates and the exchange rate of unimers. Initially, model systems will be studied for comparison with results from dynamic light scattering. PFG-STE type experiments will also be used to determine diffusion rates of monomers as functions of temperature, pressure, and fractional swelling of polymers in CO₂.  PFG-NMR experiments are unique in their ability to identify molecules, detect monomers in the presence of aggregates, and resolve these species on the basis of size.  Studies are also underway on perfluoropolyether based microemulsion systems that can bring large amounts of water into CO₂ solutions. (Project involves collaboration with Prof. J. M. DeSimone (UNC) and Prof. Keith P. Johnston, (U. Texas, Austin)

Electrophoretic NMR Studies of Soluble Gold Clusters Protected by Monolayers

Monolayer protected clusters (MPCs) are attracting attention because of fundamental issues in surface science and electrokinetic theory as well as potential applications in electronic devices, biosensors, etc.  We are characterizing water soluble MPCs with a variety of 2-dimensional NMR methods including NOESY and diffusion ordered spectroscopy (DOSY). A recently developed electrophoretic NMR (ENMR) method will be used to correlate sizes with charges for MPCs in order to gain a better understanding of transport in these systems. In particular ENMR experiments will be performed in which both the current and gradient amplitude are varied so that size information can be encoded for each electrophoretic mobility of a polydisperse MPC sample. These experiments will be performed with coaxial electrophoresis cells as well as with TCDs that permit all values of the current and RF field gradient strength to be covered in a single experiment. It should be noted that these MPCs are readily available, and that both the core size and the thickness of the ligand layer can be varied. (Project involves collaboration with Prof. R. W. Murray.)

Selected Publications from the Laboratory:

Imaging of Transient Magnetization Gratings in NMR: Analogies with Laser Induced Gratings and Applications to Diffusion and Flow, T.R. Saarinen and C.S. Johnson, Jr., J. Magn. Reson., 78, 257-270 (1988).

High-Resolution Electrophoretic NMR, T.R. Saarinen and C.S. Johnson, Jr., J. Am. Chem. Soc., 110,3332-3333 (1988).

Two-Dimensional Electrophoretic NMR for the Measurement of Mobilities and Diffusion in Mixtures, Q. He and C. S. Johnson, Jr., J. Magn. Reson., 81, 435-439 (1989).

Electrophoretic NMR, C.S.Johnson, Jr. and Q. He, Adv. Magn. Resonance, Vol. 13, Ed. W.W. Warren (Academic Press, Inc., New York, 1989) pp. 131-159.

Holographic Relaxation Studies of Probe Diffusion in Polyacrylamide Gels: Search for a Universal Equation, I.H. Park, D.A. Gabriel, and C.S. Johnson, Jr., Macromolecules, 23, 1548-1553 (1990).

Radiation Pressure Induced Gratings in Suspensions of Colloidal Particles: Dynamics of Formation and Decay, K. Xia, I.H. Park and C. S. Johnson, Jr., J. Chem. Phys., 91, 1351-1356 (1989).

Stimulated Echo Electrophoretic NMR, Q. He and C.S. Johnson, Jr., J. Magn. Reson., 85, 181-185 (1989).

A Holographic Relaxation Spectrometer with Phase Modulated Detection, R.M. Odear, I.H. Park, K. Xia, and C.S. Johnson, Jr., Rev. Sci. Instr., 62, 27-32 (1991).

Measurement of Mobility Distributions for Vesicles by Electrophoretic NMR, Q. He, D.P. Hinton, C.S. Johnson, Jr., J. Magn. Reson. 91, 654-658 (1991).

A PFG-NMR Experiment for Accurate Diffusion and Flow Studies in the Presence of Eddy Currents, S.J. Gibbs and C.S. Johnson, Jr., J. Magn. Reson., 93, 395-402 (1991).

Design and Implementation of a Shielded Gradient Coil for PFG NMR Diffusion and Flow Studies, S.J. Gibbs, K. Morris, and C.S. Johnson, Jr., J. Magn. Reson., 94, 165-169 (1991).

A Pulsed Field Gradient NMR Study of Probe Motion in Polyacrylamide Gels, S.J. Gibbs and C.S. Johnson, Jr., Macromolecules, 24, 6110-6113 (1991).

Mobility Ordered 2D-NMR Spectroscopy, K.F. Morris and C.S. Johnson, Jr., J. Am. Chem. Soc. 114, 776-777 (1992).

Diffusion Ordered 2D-NMR Spectroscopy, K.F. Morris and C.S. Johnson, Jr., J. Am. Chem. Soc. 114, 3139-3141 (1992).

Mobility Ordered 2D-NMR Spectroscopy for the Analysis of Ionic Mixtures, K.F. Morris and C.S. Johnson, Jr., J. Magn. Reson. A101, 67-73 (1993).

Effects of Chemical Exchange in Diffusion Ordered NMR Spectra, C.S. Johnson, Jr., J. Magn. Reson. A102, 214-218 (1993).

The Resolution of Discrete and Continuous Molecular Size Distributions by Means of Diffusion Ordered 2D-NMR Spectroscopy, K.F. Morris and C.S. Johnson, Jr., J. Am. Chem. Soc. 115, 4291-4299 (1993).

Transport Ordered 2D-NMR Spectroscopy, C.S. Johnson, Jr., in "Magnetic Resonance Probes of Molecular Dynamics," ed. R. Tycko, (Kluder Academic Publ., Dordrecht, 1994) chap. 10, 455-488.

From the laboratory of CSJ: A Computer Driven Bipolar Magnetic Field Gradient Driver for NMR Electrophoretic and Self-Diffusion Measurements, R.M. Boerner and W.S. Woodward, J. Magn. Reson. 106, 195-202 (1994).

Diffusion Ordered 2D-NMR Spectroscopy of Phospholipid Vesicles: Determination of Vesicle Size Distributions, D.P. Hinton and C.S. Johnson, Jr., J. Phys. Chem. 97, 9064-9072 (1993).

A Sample Spinner for Vibration Sensitive Liquid State Experiments with Application to Diffusion Ordered 2D NMR, D. Wu, W.S. Woodward and C.S. Johnson, Jr., J. Magn. Reson. A104, 231-233 (1993).

Analysis of Mixtures on the Basis of Molecular Size and Hydrophobicity by Means of Diffusion Ordered 2D NMR, K.F. Morris, P. Stilbs, and Charles S. Johnson, Jr., Anal. Chem. 66, 211-215 (1994).

Polymer-induced Non-Newtonian to Newtonian Transition in the viscoelastic CTAB/Sodium Salicylate/Water System as Studied by Diffusion ordered 2D NMR, K.F. Morris, C.S. Johnson, Jr., and T. Wong, J. Phys. Chem. 98, 603-608 (1994).

Diffusion Measurements with Magnetic Field Gradient Methods, C.S. Johnson, Jr., Encyclopedia of NMR, Wiley, New York, 1626-1644 (1995).

Electrophoretic NMR, C.S. Johnson, Jr., Encyclopedia of NMR, Wiley, New York, 1886-1895 (1995).

The Evolution of Ideas about Optical Analogies to PFGNMR and the Visualization of PFGNMR Experiments, C.S. Johnson, Jr., Encyclopedia of NMR, Wiley, New York, (1995).

Laser Light Scattering, C.S. Johnson, Jr. and D.A. Gabriel, (Dover Publications, Inc., New York, 1994). 96 pp.

Radiation Damping Effects on Relaxation Time Measurements by the Inversion-Recovery Method, D. Wu and C.S. Johnson, Jr., J. Magn. Reson. A110, 113-117 (1994).

Determination of the Binding Isotherm and Size of the Bovine Serum Albumin - Sodium Dodecyl Sulfate Complex by Diffusion-Ordered 2D NMR, Aidi Chen, Donghui Wu, and Charles S. Johnson, Jr., J. Phys. Chem. 99, 828-834 (1995).

Diffusion Coefficients, Electrophoretic Mobilities, and Morphologies of Charged Phospholipid Vesicles by Electron Microscopy and Pulsed Field Gradient NMR, D.P. Hinton and C.S. Johnson, Jr., J. Colloid and Surface Sci. 173, 364-371 (1995).

Imaging of Electroosmotic Flow Profiles with 1D Pulsed Field Gradient NMR, Donghui Wu, Aidi Chen, and Charles S. Johnson, Jr., J. Magn. Reson. A115, 123-126 (1995).

Determination of Molecular Weight Distributions for Polymers by Means of Diffusion Ordered NMR, Aidi Chen, Donghui Wu, and Charles S. Johnson, Jr., J. Am. Chem. Soc. 117, 7965-7970 (1995).

An Improved Diffusion Ordered Spectroscopy Experiment Incorporating Bipolar Gradient Pulses, Donghui Wu, Aidi Chen, and Charles S. Johnson, Jr., J. Magn. Reson. A115, 260-264 (1995).

Diffusion Ordered 2D NMR Spectroscopy in the Fringe Field of a Superconducting Magnet, Donghui Wu, and Charles S. Johnson, Jr., J. Magn. Reson. A116, 270-272 (1995).

Monolayers in Three Dimensions: NMR, SAXS, Thermal, and Electron Hopping Studies of Alkanethiol Stabilized Gold Clusters, R.H. Terrill, T.A. Postlethwaite, C.-H. Chen, C.-D. Poon, A. Tarzis, A. Chen, J.E. Hutchison, M.R. Clark, G. Wignall, J.D. Londono, R. Superfine, M. Falvo, C.S. Johnson, Jr., E.T. Samulski, and R.W. Murray, J. Am. Chem. Soc. 117, 12537-12548 (1995).

From the laboratory of CSJ: A Novel Constant-Relaxation-Time Diffusion Experiment in the Fringe Field of a Superconducting Magnet, Donghui Wu, A116, 135-137 (1995).

Advances in Diffusion Ordered NMR Spectroscopy, D. Wu, A. Chen, and C.S. Johnson, Jr., Bull. Magn. Reson. 17, 21-26 (1995).

Three-Dimensional Diffusion Ordered NMR Spectroscopy: The Homonuclear COSY-DOSY Experiment, Donghui Wu, Aidi Chen, and Charles S. Johnson, Jr., J. Magn. Reson. A121, 88-89 (1996).

Heteronuclear Detected Diffusion Ordered NMR Spectroscopy through Coherence Transfer, Donghui Wu, Aidi Chen, and Charles S. Johnson, Jr., J. Magn. Reson. A123, 215-218 (1996).

High-Pressure NMR of Polymers Dissolved in Supercritical Carbon Dioxide, Alexander Dardin, J.B. Cain, J.M. Desimone, C.S. Johnson, Jr., and E.T. Samulski, Macromolecules, 30, 3593-3599 (1997).

Fresh Spins for NMR Signal Enhancement through Programmed Sample Translation Cycles, Donghui Wu and Charles S. Johnson, Jr., J. Magn. Reson. 127, 225-228 (1997).

The Golden Age of Magnetic Resonance, Charles S. Johnson, Jr., A lead review of: Magnetic Resonance in Perspective: Highlights of a Quarter Century. Edited by Wallace S. Brey. xix + 681 pp. Academic Press, 1996. Am. Sci. 85, 180-181 (1997).

Chemical Exchange in Diffusion NMR Experiments, Aidi Chen, Charles S. Johnson, Jr., Melisa Lin, and Michael Shapiro, J. Amer. Chem. Soc. 120, 9094-9095 (1998).

Diffusion of Block Copolymers in Liquid CO₂: Evidence of Self-Assembly from Pulsed Field Gradient NMR, Judith B. Cain, Kewei Zhang, Douglas E. Betts, Joseph M. DeSimone, and Charles S. Johnson, Jr., J. Amer. Chem. Soc. 120, 9390-9391 (1998).

Diffusion Ordered Nuclear Magnetic Resonance Spectroscopy: Principles and Applications, Charles S. Johnson, Jr., Prog. NMR Spectros. 34 (3-4), 203-256 (1999).

Lecithin microemulsions for the Pulminary Delivery of Polar Compounds Utilizing Dimethylether and Propane as Propellants, Mark L. Sommerville, Judith B. Cain, Charles S. Johnson, Jr., and Anthony J. Hickey, Pharm. Develop. Tech. 5, 219-230 (2000).

Toroid Cavity Detectors for High-Resolution NMR Spectroscopy and Rotating Frame Imaging: Capabilities and Limitations, Konstantin I. Momot, Nader Binesh, Olaf Kohlmann and Charles S. Johnson, Jr., J. Magn. Reson. 142, 348-357 (2000). 

Radiation Damping in Inhomogeneous RF Fields: The Toroid Cavity Detector, Konstantine I. Momot and Charles S. Johnson, Jr., J. Chem. Phys. 115, 3992- 4002 (2001).