| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1987: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
In the presence of a large amount of added salt, we expect that due to the strong screening effect polyelectrolyte molecules in aqueous solution will behave as if they were nonelectrolyte macromolecules. We also expect that, iT the amount of added salt is sufficiently large, polyelectrolyte solutions may be regard as even poor solvent system.
Sodium polystrene sulfonate used was prepared by sulfonation of the narrow molecular weight polystyrene. The solvent used was of the NaCl-D_2O solutions. The measurements were performed with KENS-SAN instrument at KEK. The measurements were made at 40゜C.
A Kratky plot in the dilute regime clearly shows a plateau in the low angle range for a salt concentration Cs=4.17M. This suggests that the theta temperature for Cs=4.17M might be in the vicinity of 40゜C.
In the semidilute regime, from the angular dependence of the intensity the screening length was determined for every Cs and polyelectrolyte concentration Cp. From Cp dependence of the binary and ternary cluster integrals, B_1 and B_2 of polymer segments were obtained. With increasing the Debye screening length kappa^<-1>, B_1 increases monotonically from nagative to positive values and vanishes at about 1.5A showing the theta point for the solution at Cs=4.17M, and b_2 also increases with kappa^<-1>. These behaviors can be explained in terms of the increase, with the increase of kappa^<-1>, of the diameter of the correlation tube of a polyelectrolyte segment having cylindrical symmetry.
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