Dynamic light scattering in semi-interpenetrating polymer networks based on polyacrylamide and poly(N-vinylcaprolactam)

作者：Vyshivannaya O V^*; Laptinskaya T V; Makhaeva E E; Khokhlov A R

来源：Polymer Science - Series A, 2012, 54(9): 693-706.

DOI：10.1134/S0965545X12080135

Semi-interpenetrating networks based on polyacrylamide gel and linear thermosensitive poly(N-vinylcaprolactam) are obtained for the first time and studied via the method of dynamic light scattering. Contributions associated with dynamic fluctuations and frozen inhomogeneities to scattering are determined. It is shown that the ensemble-average scattering intensity strongly depends on the quantity and dimensions of frozen inhomogeneities. As temperature increases, scattering due to both dynamic fluctuations and spatial inhomogeneities tends to increase. At the temperature of the conformational transition of poly(N-vinylcaprolactam), the intensity of scattering increases abruptly, whereas the correlation function assumes the shape of a strongly stretched exponent that corresponds to high relaxation times (similar to 1 s). It is found that the relaxation-time distribution restored with the use of the inverse Laplace transform contains several modes. For all the studied networks, the correlation length of the mode of cooperative motion (the fast mode) is independent of the concentration of poly(N-vinylcaprolactam) and coincides with the correlation length of the mode of collective motion for the polyacrylamide gel.

• 出版日期2012-9