caa a22 4500 47576496X CHVBK 20180406123603.0 cr unu---uuuuu 170329e20000201xx s 000 0 eng 10.1007/s003960050020 doi (NATIONALLICENCE)springer-10.1007/s003960050020 Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene)oxide triblock copolymers at the water/air interface and in foam films [Elektronische Daten] [R. Sedev, G. H. Findenegg, D. Exerowa] The behavior of commercial poly(ethylene oxide)(PEO)-poly(propylene oxide)(PPO)-PEO triblock copolymers at the water/air interface and in microscopic foam films is studied. In aqueous solution these amphiphilic nonionic substances exhibit a surfactant-like aggregation and adsorption behavior. Even below the critical micelle concentration (cmc) the surface concentration is so high that the PEO chains are squeezed and protrude into the solution in order to accommodate to the situation at the interface. As evidenced by measurements of the ellipticity of light reflected from the free surface of the solution a PEO brush is created at the fluid interface. The microscopic foam film is used as a tool for investigating the normal interaction between two PEO brushes facing each other. Stable foam films are obtained at concentrations below the cmc and steric repulsion predominates (in 0.1 M NaCl). A brush-to-brush contact is established only at higher capillary pressures and the disjoining pressure isotherm follows de Gennes' scaling prediction. At lower pressure a softer steric repulsion occurs. It is governed by the bulk copolymer concentration and hence is fundamentally different from the brush-to-brush repellency. On the whole PEO-PPO-PEO copolymers behave as nonionic surfactants, but the large size of their molecules exemplifies the excluded-volume features. Springer-Verlag Berlin Heidelberg, 2000 Key words Amphiphilic block copolymer nationallicence Polymeric surfactant nationallicence Brush nationallicence Ellipticity nationallicence Foam film nationallicence Sedev R. Iwan-N.-Stranski-Institut für Physikalische und Theoretische Chemie, Technische Universität Berlin, Strasse des 17. Juni 112 D-10623 Berlin, Germany e-mail: sedev@chem.tu-berlin.de Tel.: +49-30-31424938 Fax: +49-30-31426602, DE aut Findenegg G. H. Iwan-N.-Stranski-Institut für Physikalische und Theoretische Chemie, Technische Universität Berlin, Strasse des 17. Juni 112 D-10623 Berlin, Germany e-mail: sedev@chem.tu-berlin.de Tel.: +49-30-31424938 Fax: +49-30-31426602, DE aut Exerowa D. Institute of Physical Chemistry Bulgarian Academy of Sciences 1113 Sofia, Bulgaria, BG aut https://doi.org/10.1007/s003960050020 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s003960050020 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sedev R. Iwan-N.-Stranski-Institut für Physikalische und Theoretische Chemie, Technische Universität Berlin, Strasse des 17. Juni 112 D-10623 Berlin, Germany e-mail: sedev@chem.tu-berlin.de Tel.: +49-30-31424938 Fax: +49-30-31426602, DE aut NATIONALLICENCE 700 1- Findenegg G. H. Iwan-N.-Stranski-Institut für Physikalische und Theoretische Chemie, Technische Universität Berlin, Strasse des 17. Juni 112 D-10623 Berlin, Germany e-mail: sedev@chem.tu-berlin.de Tel.: +49-30-31424938 Fax: +49-30-31426602, DE aut NATIONALLICENCE 700 1- Exerowa D. Institute of Physical Chemistry Bulgarian Academy of Sciences 1113 Sofia, Bulgaria, BG aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer