Functional and responsive surfaces via initiated chemical vapor deposition (iCVD)

Content Provider	Semantic Scholar
Author	Alf, Mahriah E.
Copyright Year	2011
Abstract	Stimuli-responsive polymers provide a method to control system behavior through the use of an external stimulus, such as temperature, pH, or electric fields among others. Temperature-responsive polymers, especially those based on N-isopropylacryalmide (NIPAAm), are of particular research interest due the ease of implementation of temperature changes to systems as well as the large accessible range of hydrophilic / hydrophobic switching. Initiated chemical vapor deposition (iCVD) is shown to be a useful technique for surface modification with NIPAAm-based polymers due to its ability to provide complete functional retention and applicability to “real world” substrates, which many times have varying compositions and / or microor nano-structured surfaces. The novel copolymer thin film of iCVD poly(NIPAAm-co-di(ethylene glycol) divinyl ether) (p(NIPAAm-co-DEGDVE)) is shown to exhibit a sharp lower critical solution temperature (LCST) transition, better-than or equivalent to other surfacemodification techniques, while also being able to achieve a wider range of thicknesses from the nanoto micro-scale, which is especially useful for flow control, actuator or sensor applications. The bottom-up film growth of iCVD allows for compositional gradients throughout the thickness of a polymer film. A novel NIPAAm-based copolymer with a NIPAAm-rich surface layer is developed which exhibits both fast swelling and deswelling kinetics. Quartz crystal microbalance with dissipation monitoring (QCM-D) is used to study the transition behavior of these films. These data provide valuable information relating to the polymer conformational changes throughout the transition region and help elucidate thermodynamic and mesh characteristics of the films. Finally, an application is developed which utilizes both iCVD and a complimentary technique, oxidative CVD (oCVD), to create self-heating membranes with responsive permeability characteristics. Thesis Supervisor: Karen K. Gleason Title: Alexander and I. Michael Kasser Professor of Chemical Engineering Thesis Supervisor: T. Alan Hatton Title: Ralph Landau Professor, Director, David H. Koch School of Chemical Engineering Practice
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Alternate Webpage(s)	http://web.mit.edu/cheme/news/seminars-11/Alf.pdf
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article