Studies of linear polymer dimensions of polystyrene in cyclohexane over a wide range of temperature by intrinsic viscosity

Abstract

Intrinsic viscosities ([η]) of polystyrene solutions in cyclohexane above and below the θ temperature have been measured using a capillary viscometer. The viscosity measurements were performed on five polystyrene samples with molecular weights of 6.3 × 10 4, 9.0 × 10 4, 6.0 × 10 5, 2.8 × 10 6 and 10 × 10 6. A smooth and continuous contraction was observed below the θ temperature (34.5°C). The temperature dependence of [η] can be represented by a master curve in a α 3 η|τ|M 1 2 ( g 1 2 mol − 1 2 ) versus |τ|M 1 2 ( g 1 2 mol − 1 2 ) plot, where α η = [η(T)] [η(θ)] 1 3 is a viscosity expansion factor and τ = (T − θ) T is the reduced temperature. A universal plot of reduced viscosity ( α η ) versus reduced blob parameter ( N N c ) shows the achievement of the collapsed state for the T < θ region. The prediction of the temperature blob theory is also verified for the T > θ region.