Abstract
The surface of nanopores in colloidal films, assembled from 205 nm silica spheres, was modified with poly(N-isopropylacrylamide), PNIPAAM, brushes using surface-initiated ATRP. The polymer thickness inside nanopores was controlled by the polymerization time. The diffusion through PNIPAAM-modified colloidal films was measured using cyclic voltammetry and studied as a function of temperature and polymer brush thickness. Nanopores modified with a thin PNIPAAM brush exhibited a positive gating behavior, where diffusion rates increased with increasing temperature. Nanopores modified with a thick PNIPAAM layer showed a negative gating behavior where diffusion rates decreased with increasing temperature. The observed temperature response is consistent with two transport mechanisms, one in which molecules diffuse through the nanopores whose volume increases with increasing temperature as the PNIPAAM brush collapses onto the nanopore surface (positive gating) and the second one where molecules diffuse through the porous PNIPAAM that fills the entire nanopore opening and collapses onto itself, becoming hydrophobic and impermeable (negative gating).
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
