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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 2: Focus: Field Controllable Functional Polymers I
CPP 2.4: Vortrag
Montag, 16. März 2015, 10:30–10:45, C 264
Aggregation behaviour of doubly thermo-responsive poly(sulfobetaine-b-(N-isopropylmethacrylamide) diblock copolymers — •Natalya Vishnevetskaya1, Viet Hildebrand2, Martine Philipp1, André Laschewsky2,3, Peter Müller-Buschbaum1, and Christine Papadakis1 — 1TU München, Physik-Department, Physik weicher Materie — 2Universität Potsdam, Institut für Chemie — 3Fraunhofer Institut für Angewandte Polymerforschung IAP, Potsdam-Golm
Diblock copolymers consisting of non-ionic poly(N-isopropylmethacrylamide) (PNIPMAM block) and a zwitterionic poly(sulfobetaine) (PSB block) feature both a lower and an upper critical solution temperature (LCST and UCST) in aqueous solution. Accordingly, P(SB-b-NIPMAM)is expected to form (i) micelles with PNIPMAM shell and PSB core or vice versa at low and high temperatures and (ii) unimers or large aggregates in the intermediate temperature range, depending on the chemical structure and the molar mass of the PSB block as well as on the presence of electrolyte.
The phase transition temperatures in dependence on the electrolyte concentration are investigated via turbidimetry. The aggregation behavior modulated by dual stimuli (temperature and electrolyte concentration) is studied by temperature-resolved small-angle X-ray and neutron scattering (SAXS, SANS). Aggregation of P(SB-b-NIPMAM) in deuterated water was found to occur above LCST and below UCST. The structures formed depended markedly on the blocks lengths, whereas the salt-induced structural changes were only minor.