Session J43: Physics of Copolymers II
11:15 AM–2:15 PM, Tuesday, March 22, 2011
Room: A306/307
Sponsoring Unit:
DPOLY
Chair: Bradley Olsen, Massachusetts Institute of Technology
Abstract ID: BAPS.2011.MAR.J43.6
Abstract: J43.00006 : Thermoresponsive Polymers and Block Copolymers in Ionic Liquids
12:15 PM–12:27 PM
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Abstract 
Authors:
Hau-Nan Lee
(University of Minnesota)
Zhifeng Bai
Nakisha Newell
Timothy Lodge
We recently discovered that poly(ethylene oxide) (PEO) and poly(n-butyl methacrylate) (PnBMA) exhibit two completely different types of lower critical solution temperature (LCST) phase behavior in certain ionic liquids (ILs). While typical LCST type phase diagrams were shown in PnBMA/IL systems, we observed unusual temperature-composition phase diagrams in the PEO/IL systems, in which the cloud point curves are strongly asymmetric, with the critical composition located at 80 wt {\%} of PEO. In addition, an important feature of these thermosensitive polymer/IL systems is that the LCST can be easily tuned over a wide range by blending different ILs, without changing the chemical structure of the polymers. On the basis of the LCST of PEO and the upper critical solution temperature (UCST) of poly(N-isopropylacrylamide) (PNIPAm) in ILs, we designed a PEO-PNIPAm block copolymer that exhibits interesting doubly thermosensitive self-assembly. The block copolymer forms PNIPAm-core micelles at low temperatures and transforms into PEO-core micelles at high temperatures. The critical micellization temperatures (CMT) of both blocks can be manipulated by adjusting the mixing ratio of ILs.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.J43.6