Funding: National Science Foundation, NASA, The University of Michigan

Past Students:  

Patricia Wilson (MSE, Ph.D. 1994, now at Foster Miller, Inc. in Waltham, MA),

Jun Liao (MSE, Ph.D. 1995, now at Dow Corning in Midland, MI); 

Qian Li (MSE, M.S., 1998) now in Chicago, IL;

Lebzylisbeth González-Ronda (Macro, Ph.D. 2000, now at Ford Scientific Research Laboratories, Dearborn, MI)

Current students:  

Lawrence Drummy, B. S. Physics, Rensellaer Polytechnic Institute, 1998.

Paul Miska, University of Michigan undergraduate MSE student

We are constructing and characterizing well-defined defects in electrically and optically active crystalline polymers. We have developed processing schemes to make "polymer bicrystals" with single grain boundaries of a prescribed geometry. High resolution microstructural analysis of grain boundary defects can be related to macroscopic measurements of electronic and photonic transport to reveal information about the molecular mechanisms of this response. This work makes it possible to systematically reveal the relationship between molecular architecture, morphology, and electromagnetic and optical properties. Because carrier transport in molecular systems is highly anisotropic, the properties of polymer bicrystals are extremely sensitive to the detailed rearrangements of molecules near the the interface. We have also obtained information about the micromechanisms of solid-state phase transitions during electron beam irradiation and the influence of symmetry breaking near defects on the nature and extent of chemical reactivity. Experiments have shown that the macroscopic properties of the bicrystal are extraordinarily sensitive to small misorientations between the crystals. We are currently examining small-angle grain boundaries in these systems to clarify the microscopic origin of this effect.

We are also investigating the relationship between microstructure and macroscopic properties of optoelectronically active polyalkylbithiazoles synthesized by Prof. M. David Curtis and colleagues in the University of Michigan department of chemistry. This materials are of interest for thin-film transistors, electroluminescent flat-panel displays, and chemical sensors.

Most recently we have been investigating the processing and high-resolution microstructure of pentacene, an organic molecular crystal of considerable current interest for flexible electronic components such as thin-film transistors.

Drummy, L. F., I. Voigt-Martin and D. C. Martin, "Analysis of Displacement Fields near Dislocation Cores in Ordered Polymers" Macromolecules, 34(21): 7416-7426, (2001). 

Kuebel, C. and D. C. Martin, "Influence of Structural Variations on Highesolution Electron Microscopy Images of Poly[1,6-di(N-carbazolyl)2,4-hexadiyne] Nanocrystals" Philosophical Magazine A, 81(7), 1651-1673, (2001).

Politis, J. K., M. D. Curtis, L. Gonzalez-Ronda and D. C. Martin, "Poly(nonylbisoxazole): A member of a new class of conjugated polymers" Chemistry of Materials, 12(9): 2798-2804, (2000).

Martin, D. C., Polymer Microscopy in the Year 2000 and Beyond, EUREM 2000, Brno, Czech Republic, (2000).

Kuebel, C., L. Gonzalez-Ronda, L. F. Drummy and D. C. Martin, "Defect-mediated curvature and twisting in polymer crystals" Journal of Physical Organic Chemistry, 13(12): 816-829, (2000).

Gonzalez-Ronda, L., D. C. Martin, J. I. Nanos, J. K. Politis and M. D. Curtis, "Structural characterization of electrooptically active poly(nonlbithiazole)" Macromolecules, 32(14): 4558-4565, (1999).

Delong, A., V. Kolarik and D. C. Martin, Low Voltage Transmission Electron Microscopy of Polymer Single Crystals, 4th International Conference on Electron Microscopy, Cancun, Mexico, IOP Publishing, Ltd., (1998).

Lebzylisbeth González-Ronda and David C. Martin, Lattice Imaging of Electro-Optically Active Poly(nonyl-bithiazole) (PNBT)", Macromolecules, 1997, 30(5), 1524.

Jun Liao and David C. Martin, Crystal Growth and Textured Microstructures of DCHD Diacetylene", Journal of Materials Research, 1996, 11 (11), 2921-32.

Jun Liao and David C. Martin, "Dynamic Transmission Electron Microscopy (TEM) Studies of the [1,6-di(n-carbazolyl)-2,4-hexadiyne] (DCHD) Diacetylene Monomer-Polymer Phase Transformation", Philosophical Magazine A, 1996, 74(1), 195-213.

Patricia M. Wilson and David C. Martin, "High Resolution Electron Microscopy of Crystalline Polymer Wedges", Ultramicroscopy, 1996, 62, 215-228.

Patricia M. Wilson and David C. Martin, "Quantitative Measurements of Polymer Chain-end Edge Dislocation Strain Fields by High Resolution Electron Microscopy", Macromolecules, 1996, 29, 842-851.

Jun Liao and David C. Martin, "Construction and Characterization of Grain Boundaries in Polymer Bicrystals", Macromolecules, 1996, 29, 568-580.

Jun Liao and David C. Martin, "Direct Imaging of the Diacetylene Solid-State Monomer-Polymer Phase Transformation", Science, 1993, 260, 1489-1491.

David C. Martin, "Defects in Polymer Solids", Trends in Polymer Science, 1993, 1(6), 178-183.

Patricia M. Wilson and David C. Martin, "Dislocation Mediated Lattice Bending in DCHD Poly(diacetylene) Droplets", Journal of Materials Research, 1992, 7(11), 3150-3158.

David C. Martin, Patricia M. Wilson, and Jun Liao, "Low Dose High Resolution Electron Microscopy of Polymers", Polymer Preprints, 1992, 33(1), 245-246.

Patricia M. Wilson and David C. Martin, "Lattice Bending in Poly(diacetylene) Droplets Near Surfaces", in Electrical, Optical, and Magnetic Properties of the Organic Solid State, Materials Research Society Symposia Proceedings, 1991.

Jun Liao and David C. Martin, "Defects in [1-6,Di(N-Carbazolyl)-2,4-Hexadiyne] Diacetylene Crystals", in Electrical, Optical, and Magnetic Properties of the Organic Solid State, Materials Research Society Symposia Proceedings, 1991.

David C. Martin and Edwin L. Thomas, "Grain Boundaries in Extended-Chain Polymers: Theory and Experiment", Philosophical Magazine A, 1991, 64(4), 903-922.