Laser light scattering study of intrachain and interchain associations of poly(vinyl alcohol) in aqueous solution

摘要

Laser light scattering (LLS) was used to investigate the concentration dependence of intrachain and interchain associations of poly(vinyl alcohol) (PVA) in aqueous solution after different freezing-and-thawing cycles. Our results showed that if the PVA concentration (C) was much lower than its gelation concentration (C_(gel)), the average hydrodynamic size of the PVA chains became smaller after a cryogenic treatment, which was attributed to the change of the chain conformation from an extended coil to a compact globule because the static LLS results indicated that there was no change in the weight average molecular weight (M_w). This rules out a previously speculated degradation or scission of the PVA chains. When C was higher than C_(gel), the apparent hydrodynamic size of the PVA chains was much larger and the scattering intensity became much stronger after the same cryogenic treatment, indicating the interchain association.