440747 Characterization of pH and Temperature Responsiveness in Poly(methacrylic acid)-Block-Poly(N-isopropylacrylamide)

Monday, November 9, 2015
Exhibit Hall 1 (Salt Palace Convention Center)
Ornella Tempo, Chemical Engineering, University of Connecticut, Storrs, CT, Keisha B. Walters, Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS, Erick Vasquez, Chemical Engineering, University of Dayton, Dayton, Justyn Forehand, Chemical Engineering, North Carolina State University, Raleigh, NC and Kundu Santanu, Chemical Engineering, Mississippi State University, Starkville, MS

Research Sponsor(s):This work was conducted at Mississippi State University, Starkville, MS, and was supported by the National Science Foundation [IIA-1430364; EPS- 0903787].

Stimuli responsive polymers demonstrate marked physiochemical changes under environments with different stimuli states. The objective of this effort was to study the properties changes for poly(methacrylic acid)-block-poly(N-isopropylacrylamide) (PMAA-b-PNIPAAm) in response to response to simultaneous changes in pH and temperature. In aqueous solutions, several characterization techniques were utilized to examine the macroscopic property changes and associated conformational changes of this dual-response copolymer including Fourier Transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and modulated differential scanning calorimetry (mDSC). PMAA-b-PNIPAAm in water and 2-propanol/water solutions were analyzed at various concentrations and pH. DLS and TEM both showed the change from the contracted to expanded polymer chain at the pKa.  MDSC showed the block copolymer to have a lower critical solution temperature (LCST) at polymer contraction at 32 celsius , as expected for the PNIPAAm block

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