B. Diakova et al., Thin liquid films from polyoxyethylene-polyoxypropylene-block copolymer onthe surface of fused quartz, COLL SURF A, 190(1-2), 2001, pp. 61-70
Citations number
32
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
The thickness of thin liquid films, formed from solutions of a polyoxyethyl
ene-polyoxypropylene-block copolymer (Lutrol F127 or poloxamer 407) on a su
bstrate of fused quartz was measured using the microinterferometric method.
The polymer adsorption at the air/liquid interface was studied by surface
tension measurements in the absence and presence of 0.15 M NaCl. CMC and th
e thickness of the adsorption layers were determined from the surface tensi
on data. The polymer adsorption at the SiO2/aqueous solution interface was
studied using a spectrophotometric method, based on the colored polymer-iod
ine complex, The conformation of the adsorbed molecules at both interfaces
was determined as being a 'brush'. The influence of the electrolyte concent
ration on the thickness of the thin liquid films was investigated. It was f
ound that, for NaCl concentration higher than 10(-2) M, the film thickness
remained constant. A conclusion was made that 10(-2) M NaCl was the electro
lyte concentration, above which the electrostatic disjoining pressure was f
ully suppressed and film stability might be explained by the influence of t
he steric component of the disjoining pressure. (C) 2001 Elsevier Science B
.V. All rights reserved.