J. Phys. IV France 03 (1993) C8-25-C8-28
Small-angle neutron scattering study on poly(N-isopropyl acrylamide-co-acrylic acid) copolymer solutionsM. SHIBAYAMA1, T. TANAKA2 and C.C. HAN3
1 Department of Polymer Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606, Japan
2 Department of Physics and Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A.
3 National Institute of Standards and Technology, Gaithersburg, MD 20899, U.S.A.
The structure factor (scattered intensity), I(q), for weakly charged polymer solutions of a poly(N-isopropyl acrylamide-co-acrylic acid) copolymer (NIPA/AAc) was obtained by means of small-angle neutron scattering (SANS) as a function of temperature, where q is the magnitude of the scattering vector. It was found that I(q) was well described with a Lorentz-type scattered intensity function when the temperature was lower than the so-called Θ temperature, which is about 34.6°C. Above this temperature, I(q) started to have a peak around q = 0.02Å-1, which increased with temperature. In addition, an upturn in I(q) appeared by approaching q = 0, indicating a macroscopic inhomogeneity. The structure factor was analyzed on the basis of the theory of Borue and Erukhimovich for polyelectrolytes in a poor solvent [Macromolecules, 1988, 21, 3240].
© EDP Sciences 1993