Regensburg 2002 – scientific programme
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SYPF: Struktur und Dynamik in dünnen Polymerfilmen
SYPF 2: Poster Session
SYPF 2.22: Poster
Thursday, March 14, 2002, 09:00–18:00, Poster B
Swelling/Deswelling behavior of thin polymer films containing thermosensitive PNIPAM — •Regine v. Klitzing1, Karine Glinel2, Victor Khrenov2, Klaus Tauer2, and Roland Steitz1 — 1Stranski-Laboratorium, TU Berlin, Strasse d. 17. Juni 112, D-10623 Berlin — 2MPI f. Kolloid- und Grenzflächenforschung, 14424 Potsdam
Poly–(N–Isopropylacrylamide) (PNIPAM) is well–known as thermosensitive polymer. The LCST in water is at 32 0C. The objective of the experiments which will be presented is to characterize the effect of geometrical confinement (3d to 2d) on the swelling and deswelling behavior. Therefore polyelectrolyte multilayers (film thickness 20 – 50 nm) were built by layer–by–layer deposition from aqueous solutions (A) from a charged homopolymer and a diblock–copolymer with a thermosensitive PNIPAM block, (B) from two statistical co-polymers of opposite charge both containing NIPAM units and (C) from thermoinsensitive homopolymers (reference samples). Thermal behavior and subsequent structural changes of the functionalized films against D2O were investigated by neutron reflectometry. The thermosensitive films showed a distinct decrease in thickness at elevated temperature (> 30 0C) while the reference samples did not. Although the phase transition of PNIPAM is reversible in solution, it becomes irreversible if PNIPAM is embedded in a polyelectrolyte film. The influence of the PNIPAM position in the film on the transition behavior will be investigated.