A series of four pairs of bismaleimide and bisfuran monomers were combined to make thermally reversible linear polymers. The monomers were prepared using diamines having different spacer chemistries, n-octyl, cyclohexyl, phenyl, and ethylenedioxy, such that a relatively constant spacer dimension among the four monomers was achieved. Heating of the bismaleimide/bisfuran couples resulted in low-viscosity, easily processable liquids. Subsequent cooling to room temperature resulted in the formation of hard films, with the rate of hardening varying significantly within the series of compounds. The rate and degree of polymerization were deter-mined using 1 H NMR spectroscopy and were both found to be dependent on the chemistry of the spacer group, as was the film rheology, which was measured using nanoindentation. Adhesion of the polymers was quantified by measurement of their tensile adhesive strength, and this was also found to be spacer dependent. Polymerization reversibility was verified using 1 H NMR spectroscopy.

Phase separation of polystyrene (PS) and poly(methyl methacrylate) (PMMA) blends was used as a means to segregate PS‐ or PMMA‐functionalized single‐walled carbon nanotubes (SWNTs) in thin films. Dilute solutions (5 wt % in THF) of 1:1 PS/PMMA blends containing the functionalized nanotubes were spin cast and annealed at 180 °C for 12 h. Two different polymer molecular weights were used (Mn = 8000 or Mn = 22,000), and were of approximately equivalent molecular weight to those attached to the surface of the nanotubes. Nanotube functionalization was accomplished using the Cu(I)‐catalyzed [3 + 2] Huisgen cycloaddition, in which alkyne‐decorated nanotubes were coupled with azide‐terminated polymers, resulting in polymer‐SWNT conjugates that were soluble in THF. Characterization of the annealed films by scanning Raman spectroscopy, which utilized the unique Raman fingerprint of carbon nanotubes, enabled accurate mapping of the functionalized SWNTs within the films relative to the two phase‐separated polymers. It was found that nanotube localization within the phase‐separated polymer films was influenced by the type of polymer attached to the nanotube surface, as well as its molecular weight. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 450–458, 2009

This paper discusses the use of Rietveld analysis to solve crystal structures of titanyl phthalocyanines. Rietveld analysis is based on whole pattern fitting in which every point in the x-ray powder diffraction pattern is used as a measure of one or more Bragg diffraction peaks. Thus the refinement of relatively complicated crystal structures from x-ray patterns containing a relatively small number of resolved diffraction peaks is enabled. Various profile-fitting functions used in Rietveld analysis were parameterized and tested against known crystal structures of type I and type II titanyl phthalocyanine. It was found that a split Pearson VII function was found to best correct for preferred orientation effects observed in the x-ray patterns. The final goodness-of-fit parameters were R(Bragg) = 0.17 and 0.13 for type I and type II structures, respectively.A computer program was used to generate several unit cells for type IV titanyl phthalocyanine. These unit cells were tested by stereochemical packing analysis to first determine which unit cells allowed for good intermolecular packing arrangements. Energy minimized models were then used as phasing models for Rietveld refinement. A triclinic structure with space group P-i having an x-ray goodness-of-fit parameter R(Bragg) = 0.24 was proposed as the most probable crystal structure for type IV titanyl phthalocyanine. The unitcell parametersarea = 1.083 nm, b = 1.312 nm, c = 0.996 nm, alpha = 72.28 degrees, beta = 77.25 degrees and gamma = 104.48 degrees. There are two molecules in the unit cell related by a center of inversion. 160/ SPIE Vol. 1670 Color Hard Copy and Graphic Arts (1992) 0-81 94-0824-7/92/$4.00 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/07/2015 Terms of Use: http://spiedl.org/terms