Hierarchical self-assembly of polyelectrolytes at interfaces
- Event time: 1:00pm
- Event date: 3rd September 2001
- Speaker: Christiane A Helm (Universität Greifswald Germany)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
A diblock copolymer consisting of a fluid hydrophobic block and a PSS (poly(styrene sulfonate)) block self-organizes at the water surface as a monolayer. Two polyelectrolyte brush phases can be distinguished with x-ray reflectivity: at low salt the osmotically swollen brush characterized by stochiometric ion incorporation and constant thickness; at high salt (> 0.1 M) the salted brush, which shrinks both with molecular area and subphase salt, according to the predicted power laws. PSS adsorbed onto a cationic lipid monolayer is studied. Flat and coiled adsorption can be distinguished, depending on salt concentration, monolayer surface charge and degree of polymerisation. Multilayers formed by alternate adsorption of polycations and polyanions show a similar dependence on solution parameters. Investigations with the SFA indicate chain interpenetration in multilayers.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..