Dresden 2003 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Chemische Physik und Polymerphysik

CPP 21: POSTER B

CPP 21.16: Poster

Dienstag, 25. März 2003, 19:00–21:00, ZEU/250

Interactions between PNIPAAM and surfactants in bulk and in thin films — •Genlin Tian¹, Victor Khrenov², Klaus Tauer², and Regine v. Klitzing¹ — ¹Stranski-Laboratorium, TU Berlin, Strasse d. 17. Juni 112, D - 10623 Berlin — ²MPI für Kolloid- und Grenzflächenforschung, D - 14424 Potsdam

In water solutions Poly(N-isopropylacrylamide) (PNIPAAM) undergoes a coil-globule transition at around 32 ⁰C. From DSC study, it is known that ionic surfactants can suppress the phase transition while nonionic surfactants does not show any pronounced influence. This means that there is a stronger interaction between PNIPAAM and cationic and anionic surfactants, and the hydrophobic tails of the ionic surfactant aggregate with carbon the backbone of PNIPAAM to form aggregates. These could stop the change of the coil to globule trasnsition of PNIPAAM. Free-standing films have been formed from aqueous solutions containing PNIPAAM and surfactant. At room temperature, stable films could be obtained, but at high temperature, the films become thinner until they break at very low disjoining pressure. With nonionic surfactants, Newton black films (NBF) are obtained before and after the phase transition. This indicates that the polymer has been pressed out of the film independently of the temperature.