Polymer, Vol.36, No.3, 599-602, 1995
A Study on the Transition of Linear Polymer Dimension from Theta to Collapsed Regime by Intrinsic-Viscosity Measurement for Poly(Ethyl Methacrylate) in Isopropyl-Alcohol
The intrinsic viscosity of poly(ethyl methacrylate) in isopropyl alcohol (propan-2-ol) around the theta (theta) temperature was measured using a capillary viscometer. Contraction and collapse were observed below the theta temperature. Because of experimental difficulties around the cloud point, mathematically curve-fitted experimental points were obtained instead of experimental data at lower temperatures. The temperature dependence of the intrinsic viscosity can be represented by a master curve in a plot of alpha(eta)(3)tau($) over bar M(w)(1/2) (g(1/2) mol(-1/2)) vs. tau($) over bar M(w)(1/2) (g(1/2) mol(-1/2)), where alpha(eta) = ([eta](T)/[eta](theta))(1/3) is the viscosity expansion factor and tau = (T-theta)/T is the reduced temperature. A universal plot of reduced viscosity vs. reduced blob parameter (N/N-c) shows the attainment of the collapsed state below the theta temperature. The results in this work have been compared with previously published results.
Keywords:PHASE-TRANSITION;TEMPERATURE-DEPENDENCE;HYDRODYNAMIC RADIUS;DYNAMICAL PROPERTIES;MOLECULAR-WEIGHT;DNA CONDENSATION;FLEXIBLE COILS;METHYL ACETATE;POLYSTYRENE;CYCLOHEXANE