| Abstract
| - Monte Carlo simulations have been performed to examine the scaling with chain length ofthe upper critical solution temperature (Tc) of binary, symmetric blends of polymers. Critical parameterswere obtained by histogram reweighting analysis of semigrand canonical ensemble simulations near thecritical temperature. For several continuum space polymeric models, it is found that Tc/ε scalesapproximately as either ρc(A + B N) or ρcN/(B-1 + A/), where N is chain length, ρc is the density atTc, ε is a chemical mismatch parameter, and A and B are constants that depend on the specificcharacteristics of the model. Constant A provides a measure of the correction to the Flory−Huggins'prediction Tc ∼ N. The effect of such correction term becomes unimportant for large N, ε, and temperature.Excellent agreement is found, however, with the mean-field prediction that χE ∼ 2/N (for all systemsstudied), where χE is a continuum space, enthalpic “chi” parameter which takes into account the variationsof local structure of the fluid for different chain lengths at the critical point.
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