showing 6 related works from this author
Towards completely miscible PMMA nanocomposites reinforced by shear-stiff, nano-mica
2014
Abstract Optimizing the reinforcement of polymers with nanoplatelets requires optimization of the aspect ratio and the moduli of the filler while providing a complete stress transfer. Employing a novel shear-stiff, nano-mica with large aspect ratio, we focus on maximizing the interfacial interaction between filler and matrix. External surfaces of the nano-mica were selectively modified by a polycationic macro-initiator and two PMMA-polymer brushes of length below and above critical entanglement length, respectively, and the mechanical properties of the three PMMA nanocomposites were measured. The multiple electrostatic anchoring groups of the macro-initiator not only provide reliable adhesi…
Static and dynamic light scattering by aqueous polyelectrolyte solutions: effect of molecular weight, charge density and added salt
1990
Abstract Aqueous solutions of quaternized poly(2-vinylpyridine) were investigated by static (SLS) and dynamic (DLS) light scattering over a wide range of polyelectrolyte, c pe , and salt concentrations, c s (10 −3 ≤ c pe ≤ 10 2 gl −1 , 10 −5.5 ≤ c s ≤ 10 −1 moll −1 ). Using DLS the cooperative diffusion coefficient D was measured as a function of c pe and c s . D exhibits a characteristic behaviour in each of three different concentration regimes. In the ‘dilute lattice’ regime, where λ = c pe c s ⪡ 1 , one diffusion coefficient is observed. In the transition regime, where λ ≈ 1, D increases with increasing polyelectrolyte concentration and a slow diffusive mode gradually appears. For λ ⪢ 1…
Poly(styrene sulfonate) self-organization: electrostatic and secondary interactions
2004
We investigate the self-organization of PSS in brushes and polyelectrolyte multilayers with X-ray, neutron and optical reflectivity. The electrostatic force dominates brush phases and adsorption behavior, additionally we find evidence of a strong hydrophobic force: (i) within amphiphilic diblock copolymer monolayers, a PSS monolayer adsorbs flatly to the hydrophobic block, (ii) on temperature increase (and with screened electrostatic forces), more PSS is adsorbed onto oppositely charged surfaces, and (iii) a polyelectrolyte multilayers shrinks when heated at 100% r.h. The latter two effects are consistent with the well-known increase of the hydrophobic force on heating: The increased PSS su…
Polyelectrolyte Brushes Grafted at the Air/Water Interface
1997
A new approach for the study of grafted polyelectrolytes is investigated: monolayers at the air/water interface of block copolymers consisting of a liquid hydrophobic and a polyelectrolyte block. ...
Interfacial stabilization by soft Janus nanoparticles
2016
Abstract The stabilization of water/air, water/oil and water/solid interfaces by Janus particles with polystyrene (PS) and poly(methacrylic acid) (PMAA) hemispheres was systematically investigated. The stabilization of these interfaces is of relevance for the formulation of foams, emulsions and dispersions. The Janus particles were prepared from micellar solutions of polystyrene-b-polyisoprene-b-poly(tert-butyl methacrylate) (PS-PI-PtBMA) triblock terpolymers by selective cross-linking of the polyisoprene domain on a multi-gram scale, followed by hydrolysis of the PtBMA block. For the investigation of water/oil-emulsions a series of hydrophobic oils (paraffin oil, xylene, peanut oil, isopro…
Chemically driven phase separation in black lipid membranes and its coupling to membrane functions
1992
Abstract We analysed the single-channel current fluctuations of gramicidin in bimolecular lipid membranes in order to demonstrate (i) the influence of protein binding to the lateral organisation of a mixed membrane, and (ii) how this couples to the function of the ionophore. Examples of phase separations induced by synthetic polyelectrolytes, as models for peripheral membrane proteins, and specific ligand-receptor interactions are presented and discussed in view of the important lateral order-function relationship in biomembranes.