Thermoreversible gels of poly(vinyl alcohol)/Congo red in aqueous solutions have been studied by dynamic light scattering. Below Tgel(≈43^∘C), a speckle pattern appeared, while it disappeared for T>Tgel. This indicates that nonergodicity observed in chemically cross-linked gels also exists in thermoreversible physical gels. Analogous to the {β} and {α} relaxations of glasses, the intensity correlation function showed a power-law behavior for T≤Tgel and a stretched exponential behavior for T≥Tgel, respectively, while the thermal fluctuations characteristic of polymer gels were present independent of Tgel.
No takes yet. Share an insight, caveat, or question.
Ikkai et al. (1999) studied this question.