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Graduate Student Office: 226 Mason Lab Phone: (203) 436-4059 |
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Ph.D. Candidate, Chemical Engineering, Environmental Engineering Program, Yale University Meagan is a PhD candidate interested in the environmental applications and implications of emerging technologies. Her dissertation will focus on carbon nanotubes, including research towards high-flux desalination membranes incorporating carbon nanotubes and assessment of the bacterial cytotoxicity of carbon nanotubes in aquatic systems. Meagan is also interested in the social implications and public risk perception of emerging technologies, and she is currently developing both theoretical and empirical models to describe the relationship between public trust in regulatory agencies and public perceptions of nanotechnology. |
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Thin polymer films (~ 1-10 um) incorporating singly dispersed, vertically aligned carbon nanotubes have a diverse set of potential applications. This project aims to direct the vertical alignment of SWNTs in thin films by using magnetic field aligned lyoptropic surfactant mesophases as structure directing templates. The short alkyl tails of the surfactant impart negative diamagnetic anisotropy to worm-like micelles and lead to parallel alignment of the liquid crystalline (LC) director in an applied magnetic field. The nanotubes orient preferentially with their long axis parallel to the director field of the mesophase, thus promoting their vertical alignment in the system. The LC mesophase incorporates monomers that are polymerized by UV exposure after nanotube alignment to form the polymer matrix. X-ray scattering and optical spectroscopy are used to characterize the field-guided assembly process.
Figure 2:Wide Angle X-ray Scattering of Host Matrix: Alignment of wormlike micelles in the direction of the applied field evident from enhanced intensity along vertical axis. Scattered intensity vs. scattering vector derived by circular integration of the WAXS scattering pattern. The ratios of the q vectors indicate that the sample is composed of hexagonally packed cylinders. |
Figure 1a: Polarized optical micrograph of a hexagonally ordered lyotropic host mesophase before alignment. Figure 1b: LC Alignment under Magnetic Field: The 4 images correspond to 4 90-degree separated orientations of the analyzer. The sample was aligned with the long axis of cylindrical micelles parallel to the field direction.
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