Effects of Ionic Strength and pH on the Electrophoretic Mobility and Viscosity of Poly (N, N-Dimethyl Diallyl Ammonium Chloride)

Electrophoretic mobilities and viscosities of poly (N, N-dimethyl diallyl ammonium chloride) (PDDA) were measured in the pH range of 3-10, using buffer solutions at the ionic strengths, μ of 0.02-1.0. The dependences of the limiting mobilities (Uc→o) and intrinsic viscosities ([η]) on μ (at pH 7.0) and pH (at μ 0.05, 0.1, and 0.2), and the dependence of [η] on Uc→o expressed by, μ or pH were investigated. The results are as follows : (1) Uc→o and [η] decrease monotonically with increasing μ. (2) Uc→o, and [η] are almost independent of pH where it is smaller than 5 and larger than 7, but decrease with increasing pH where it is from 5 to 7. (3) The plots of [η] vs. Uc→o are straight lines passing through the origin at μ≥0.1. On the basis of the above-mentioned results, the effects of μ and pH on the charge and conformation of PDDA inn are estimated.