1. From pH- to Light-Response:
Postpolymerization Modification of Polymer Brushes
Grafted onto Microporous Polymeric Membranes
Matthias Dübner†,‡, Maria-Eleni Naoum†, Nicholas D. Spencer‡, Celestino Padeste†,*
† LMN, Paul Scherrer Institute, ODRA/105, 5232 Villigen PSI, Switzerland
‡ LSST, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
ACS Omega 2017, 2, ; DOI: /acsomega.6b00394

2. Background Smart Membranes Motivation
Smart membranes allow rapid, remote-controlled switching of their interfacial properties:
Swelling behavior
Permeability
Interactions with ions and biomolecules
Switching originates from external stimulation:
Changes in pH
Temperature
Concentration of metal ions
Exposure to light
Smart Membranes
Schematic Illustrattion of a smart membrane changing its flux reversibly upon external stimulation.
Motivation
Establish facile and versatile method for the fabrication of responsive polymeric membranes
Determine the parameters that cause changes in interfacial properties

3. Fabrication of pH-Responsive PMAA Brushes
Anpassungen in Textbox (grafting level of membranes nicht brushes + kürzung)
The grafting level (GL) of pH-responsive membranes increases with increasing activation time, reaching a maximum at 4 min of plasma exposure:
→ Change from a very delicate microporous network to an increasingly closed system

4. Switching of Interfacial Properties Upon Change in pH
CA measurements
Flux measurements
Plots angeschrieben
PMMA ersetzt durch PMAA
Letzter punkt rausgenommen (genügt, wenn das im gesprochenen Text kommt)
PMAA-modified surfaces switch their water contact angle (CA) upon a change in pH
Reversible switching of the flux through membranes under different pH conditions:
→ Dependence on GL and swelling behavior

5. Postpolymerization Modification of Photochromic Membrane
Introducing light-responsiveness via postpolymerization modification of PMAA brushes:
Color switch upon UV-light exposure from light pink to deep purple: → spiropyran (SP) – merocyanine (MC) transition
Struktur etwas angepasst und UV exposed part angeschrieben
Vis UV

6. Switch of Interfacial Properties Upon Light Exposure
CA measurements
Flux measurements
Reversible switching of the flux through membranes upon alternating irradiation:
→ Almost independent on the GL
→ Driven by the switch in wettability

7. Summary The Switch in flux properties is dominated by:
pore size effects for pH-induced stimulation
wettability changes for photon-induced stimulation
Da das letzte slide überladen war und es gut ist, die TOC-grafik nochmals zu bringen, habe ich dies eingefügt, und dafür das letzte gekürzt

8. Conclusions Acknowledgments
We present a simple and versatile method for the fabrication of responsive polymeric membranes
We demonstrate reversible switching in wettability and permeability upon external stimulation
We see application potential for controlled separation or transport of dissolved species
Acknowledgments
Swiss National Science Foundation
(SNF, _159758/1)
Paul Scherrer Institute and ETH Zurich, Switzerland
Matthias Dübner
Maria-Eleni Naoum
Ein Punkt rausgenommen
Bild von Marilena in der Grösse angepasst
Nicholas D. Spencer
Celestino Padeste