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New controlled release systems produced by self-assembly of biopolymers and colloidal particles at fluid-fluid interfaces
The formation of polyelectrolyte multilayers (PEMs) is investigated using a silicon-on-insulator based thin film resistor which is sensitive to variations of the surface potential. The buildup of the PEMs at the silicon oxide surface of the device can be observed in real time as defined potential shifts. The influence of polymer charge density is studied using the strong polyanion poly(styrene sulfonate), PSS, combined with the statistical copolymer poly(diallyl-dimethyl-ammoniumchloride-stat-N-methyl-N-vinylacetamide), P(DADMAC-stat-NMVA), at various degrees of charge (DC). The multilayer formation stops after a few deposition steps for a DC below 75%. We show that the threshold of surface charge compensation corresponds to the threshold of multilayer formation. However, no reversion of the preceding surface charge was observed. Screening of polyelectrolyte charges by mobile ions within the polymer film leads to a decrease of the potential shifts with the number of layers deposited. This decrease is much slower for PEMs consisting of P(DADMAC-stat-NMVA) and PSS as compared to PEMs consisting of poly(allylamine-hydrochloride), PAH, and PSS. From this, significant differences in the dielectric constants of the polyelectrolyte films and in the concentration of mobile ions within the films can be derived. [hide]
Scientific Board
Andreas Bausch
TU Munich, Germany ►
Peter Fischer
ETH Zurich, Switzerland ►
Anne-Marie Hermansson
SIK, Sweden ►
Martin Kroger
ETH Zurich, Germany/Switzerland ►
Erik van der Linden
Wageningen UR, The Netherlands ►
Niklas Loren
SIK, Sweden ►
Leonard Sagis
Wageningen UR, The Netherlands ►
Erich Windhab
ETH Zurich, Switzerland ►
Klaas-Jan Zuidam
Unilever, The Netherlands ►
Scientific Stuff
Manuela Duxenneuner
ETH Zurich, Switzerland ►
Sophia Fransson
SIK, Sweden ►
Nam-Phuong Humblet-Hua
Wageningen UR, The Netherlands ►
Joeska Husny
ETH Zurich, Australia/Switzerland ►
Orit Peleg
ETH Zurich, Israel/Switzerland ►
Cyrille Vezy
TU Munich, Germany ►
Varvara Mitropoulos
ETH Zurich, Switzerland ►
Associated Scientists
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SY Tee, AR Bausch, PA Janmey,
The mechanical cell
CURRENT BIOLOGY 19 (2009) R745 ►Selected conferences (co-)organized by project members
8th World Congress on Computational Mechanics WCCM8 2008
30 June - 5 July 2007, Venice, Italy ►13 May 2025
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