SKM 2021 – wissenschaftliches Programm
CPP 8.32: Poster
Mittwoch, 29. September 2021, 17:30–19:30, P
Co-nonsolvency behavior of responsive polymers in thin film/vapor systems — •Christina Geiger1, Morgan Le Dû1, Anna Lena Oechsle1, Peixi Wang1, Suo Tu1, Robert Cubitt2, and Peter Müller-Buschbaum1 — 1TU München, Physik-Department, LS Funktionelle Materialien, 85748 Garching, Germany — 2Institut Laue-Langevin, 38000 Grenoble, France
After exposure to mixed water/cosolvent vapor, hydrated thin films of stimuli-responsive block copolymers with PNIPAM or PNIPMAM blocks exhibit a co-nonsolvency behavior. In a rapid film contraction, in either system, both water and cosolvent are expelled. Film swelling and contraction kinetics from saturated vapor are investigated in time-of-flight neutron reflectometry (ToF-NR) with simultaneous spectral reflectance (SR). Molecular interactions of the solvent with the respective polymer chains are analyzed with Fourier-transform infrared (FTIR) spectroscopy. In our latest study with PNIPAM, we focus on the swelling behavior in mixed vapors starting not from the hydrated, but from the dry film state. A minimum in reached thickness due to the co-nonsolvency effect is found, which is reversely related to the interaction strength of polymer chains facilitated by the present water/cosolvent ratio.