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Croatica Chemica Acta, Vol.80 No.3-4 November 2007. -

Effects of pH and additives NaCl, Na2SO4, NaSCN and urea on the adsorption of an ABA

triblock copolymer F127 with polyethylene oxide as the A blocks and polypropylene oxide as

the B blocks, at the interfaces of wetting films, on film drainage and on the interaction forces

in these films are examined using ellipsometry and a thin film balance technique. The influence

of these additives on micellization are studied by static light scattering. The main findings

are that all additives reduce the adsorption at the silica surface and retard the film drainage.

Moreover, high pH values ≈10 destabilize the wetting film if 0.1 mol dm–3 NaCl is present.

The reduction of the adsorbed amount appears to be correlated with a dramatic slow down of

film drainage. The slow drainage as well as the destabilization of the film is attributed to bridging

attraction between a densely covered air-water interface and a very sparsely covered silicawater

interface.

aqueous wetting films; disjoining pressure; water-soluble polymers; block copolymer; surfactants; salting-in; salting-out



Autor: O. V. Eliseeva - ; Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Wageningen, The Netherlands N. A.

Fuente: http://hrcak.srce.hr/



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