Design Strategies for Reduced-scale Surface Composition Gradients via CVD Copolymerization

Authors

  • Yaseen Elkasabi,

    1. Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48109 (USA)
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  • Aftin M. Ross,

    1. Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, (USA)
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  • Jonathan Oh,

    1. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (USA)
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  • Michael P. Hoepfner,

    1. Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (USA)
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  • H. Scott Fogler,

    1. Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (USA)
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  • Joerg Lahann,

    1. Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, (USA)
    2. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (USA)
    3. Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109 (USA)
    4. Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (USA)
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  • Paul H. Krebsbach

    Corresponding author
    1. Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48109 (USA)
    2. Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, (USA)
    • Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, North Campus Research Complex, 010-A149 2800 Plymouth Ave., Ann ArborMI 48109 (USA)

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  • The authors would like to acknowledge a NSF major instrumentation grant (DMR-0420785), as well as an NIH T-32 training grant (DE007057-36) and NIH grant (DE018890, PHK). J.L. acknowledges support from DTRA under project HDTRA1-12-1-0039. A.M.R. would also like to acknowledge support from the University of Michigan Rackham Predoctoral Fellowship.

Abstract

A new method for generating and modeling reduced-scale copolymer gradients by CVD is reported. By exploiting diffusion through confined channels, functionalized [2.2]paracyclophanes are copolymerized into their poly(p-xylylene) (PPX) analogues as a composition gradient. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) are used to verify the gradient composition profiles. Gradients are deposited on both flat substrates and 3-dimensional cylinders. Both the thickness and compositional profiles are fitted to a diffusion-based model using realistic physical parameters. The derived equation can be generalized and optimized for any copolymerization gradient through a confined geometry, thus allowing for broad applicability to other copolymer systems.

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