Monolayer films of Ps-b-PEO diblock copolymers at the air/water- and an oil/water-interface

• Published in: Colloid and polymer science Vol. 276; no. 6; pp. 496 - 502
• Main Authors: ROTHER, G, FINDENEGG, G. H
• Format: Journal Article
• Language: English
• Published: Berlin Springer 20-07-1998; Springer Nature B.V
• Subjects: Applied sciences; Copolymers; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Surface properties; Monolayer; Property composition relationship; Interface tension; Temperature effect; Air water interface; Ethylene oxide copolymer; Experimental study; Concentration effect; Liquid liquid interface; Diblock copolymer; Time curve; Interface activity; Amphiphilic polymer; Styrene copolymer
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s003960050271

Amphiphilic diblock copolymers consisting of a hydrophobic polystyrene block (PS) and a hydrophilic poly(ethylene oxide) block (PEO) with block sizes of 1000 or 3000g/mol for both blocks were studied at the air/water and toluene/water interface. Measurements of the film pressure π of spread monolayers at the water surface reveal two limiting regimes of the π-a^sub m^ isotherms, in which the mean molecular area a^sub m^ is determined either by the size of the hydrophilic or the hydrophobic blocks of the PS-PEO molecules. The interfacial activity of the block copolymers at the toluene/water interface was studied by measuring the interfacial tension σ over a wide range of concentrations. Pronounced differences in the temperature dependence of the interfacial tension were observed, depending mostly on the block length of the hydrophilic PEO block. From the temperature dependence of σ it is inferred that for the block copolymers with the PEO block size of 3000g/mol the phase inversion temperature (PIT) is well above 60°C while for those with a PEO block size of 1000g/mol the PIT is below or near 25°C in the toluene/water system.[PUBLICATION ABSTRACT]