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

Abstract

The intrinsic viscosity of poly(ethyl methacrylate) in isopropyl alcohol (propan-2-ol) around the theta (θ) temperature was measured using a capillary viscometer. Contraction and collapse were observed below the θ 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 α η 3|τ| M w 1 2 ( g 1 2 mol − 1 2 ) vs. |τ| M w 1 2 ( g 1 2 mol − 1 2 ) , where α η=([η] T/[η] θ) 1 3 is the viscosity expansion factor and τ=( T- θ)/ 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 θ temperature. The results in this work have been compared with previously published results.