Dynamic and static fluctuations in polymer gels studied by neutron spin-echo

Kanaya, Toshiji*; Takahashi, Nobuaki; Nishida, Koji*; Seto, Hideki*; Nagao, Michihiro*; Takeda, Takayoshi*

We report neutron spin-echo measurements on three types of poly(vinyl alcohol) (PVA) gels. The first is PVA gel in a mixture of dimethyl sulfoxide (DMSO) and water with volume ratio 60/40, the second is PVA gel in an aqueous borax solution and the third is chemically cross-linked PVA gel. The observed normalized intermediate scattering functions I(Q,t)/I(Q,0) were very different among them. The I(Q,t)/I(Q,0) of the first and third gels showed a non-decaying component in addition to a decaying component, but the second one did not have the non-decaying one. This clearly indicates that the fluctuations in the first and third PVA gels consist of static and dynamic fluctuations whereas the second PVA gel does include only the dynamic fluctuations. The dynamic and static fluctuations of the PVA gels were analyzed in terms of a restricted motion in the gel network and the Zimm motion, respectively.