Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 34: Poster: Elastomers and Gels
CPP 34.5: Poster
Mittwoch, 16. März 2011, 17:00–19:00, P2
Cononsolvency in thermoresponsive PNIPAM-based block copolymers — Gabriele De Paoli1, Sebastian Jaksch1, Anna Miasnikova2, André Laschewsky2, Peter Müller-Buschbaum1, and •Christine M. Papadakis1 — 1Physikdepartment, Physik Weicher Materie, TU München, Garching — 2Institut für Chemie, Universität Potsdam, Potsdam
Thermoresponsive polymers are smart materials which have attracted
great attention because of their potential applicability e.g. in
controlled ultrafiltration [1]. Among these, poly(N-isopropyl acryl
amide) (PNIPAM) exhibits in water a lower critical solution
temperature (LCST) of ca. 32 ∘C. Interestingly, the
insolubility can also be triggered by the addition of alcohols, which,
in the pure state, are good solvents for PNIPAM [2]. This is the
so-called cononsolvency phenomenon.
Herein, we report on the
cononsolvency behavior of micelles formed by amphiphilic block
copolymers having a long hydrophilic PNIPAM block and a short
hydrophobic polystyrene block. Turbidity and dynamic light scattering
experiments clearly show that methanol acts as a cononsolvent for
these polymeric systems in water. Compared to the homopolymer, the
amphiphilic block copolymers are unexpectedly more sensitive to the
presence of methanol. Moreover, a control over the size of aggregates
formed in solution is obtained by adjusting the amount of cononsolvent
in the binary solutions.
Y.S. Park et al.,
Langmuir 14, 910 (1998).
[2] H.G. Schild et al. Macromolecules 24, 948
(1991).