Hydrodynamic properties of poly(1‐vinyl‐2‐pyrrolidone) molecules in dilute solution

Abstract

Abstract The translational diffusion coefficient D 0 , the sedimentation coefficient S 0 , and the intrinsic viscosity [η] of samples and fractions of poly(1‐vinyl‐2‐pyrrolidone) were measured in a 0,1 M solution of sodium acetate in the molecular weight range 2 ≤ M · 10 −3 ≤ 2200. For M > 4 · 10 4 the following relationships were obtained: [η] = 8,86 · 10 −5 · M 0,74 , D 0 = 2,42 · 10 −4 · M −0,58 , and S 0 = 2,14 · 10 −15 ·. M 0,42 . For M < 4 · 10 4 the corresponding relations are [η] = 5,0 · 10 −4 · M 0,56 , D 0 = 1,29 · 10 ‐4 · M −0,52 and S 0 = 1,15 · 10 −15 · M 0,48 . The hydrodynamic invariant is A 0 = (3,2 ± 0,25) · 10 −17 J · K −1 · mol −1/3 and the sedimentation parameter β s = (1,3 ± 0,17) · 10 7 mol −1/3 . The temperature coefficient of the intrinsic viscosity is negative, viz. Δ ln[η]/Δ T = −6,3. 10M −3 K −1 . The evaluation of the length of the Kuhn segment A and the hydrodynamic diameter d of chains representing the molecules of PVP in solution was conducted on the basis of the theory for the hydrodynamic properties of a wormlike necklace taking into account the excluded volume effects. The values of A agree with those obtained from the Burchard‐Stockmayer‐Fixman and Cowie‐Bywater equations, A = (2,1 ± 0,3) nm and d = (0,5 ± 0,13) nm.