Tuning the thermoresponsiveness of weak polyelectrolytes by pH and light: lower and upper critical-solution temperature of poly(N,N-dimethylaminoethyl methacrylate).
نویسندگان
چکیده
The presence of multivalent counterions induces an upper critical solution temperature (UCST) in addition to the known lower critical solution temperature (LCST) of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA). The LCST-type cloud points can be adjusted by pH of the buffer, whereas the UCST-type cloud points can be adjusted by the concentration of trivalent counterions. High pH favors the LCST transition, whereas lower pH extends the UCST-type miscibility gap at constant concentration of trivalent counterions. By use of hexacyanocobaltate(III) as a trivalent counterion, we can even switch off again the UCST-behavior by UV-illumination (photoinduced dissolution).
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ورودعنوان ژورنال:
- Journal of the American Chemical Society
دوره 129 47 شماره
صفحات -
تاریخ انتشار 2007