Sharp Hydrophilicity Switching and Conformality on Nanostructured Surfaces Prepared via Initiated Chemical Vapor Deposition (iCVD) of a Novel Thermally Responsive Copolymer

Authors

  • Mahriah E. Alf,

    1. Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA
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  • Paul D. Godfrin,

    1. Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA
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  • T. Alan Hatton,

    1. Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA
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  • Karen K. Gleason

    Corresponding author
    1. Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA
    • Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA Fax: (+617) 258 5042.
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Abstract

A novel thermally responsive copolymer p(NIPAAm-co-DEGDVE) is synthesized using the substrate independent method of iCVD and exhibits a sharp lower critical solution temperature (LCST) transition centered at ≈28.5 ± 0.3 °C determined via quartz crystal microbalance measurements with dissipation monitoring (QCM-D). Swelling with water below the LCST produces a reversible change of ≈3× in film thickness. The layer is conformal on nanostructured surfaces including MWCNT forests and electrospun nanofiber mats. Modified planar substrates exhibit ≈30°change in static contact angle over the LCST, while through conformal coating on nanostructured substrates changes in static contact angle up to 135° are achieved. Additionally, coated surfaces exhibit temperature sensitive BSA adsorption measured by QCM-D and is reversible as shown through fluorescence imaging of a coated electrospun nanofiber mat.

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