About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Macromolecules
Paper
Temperature Dependence of Tracer Diffusion of Homopolymers into Nonequilibrium Diblock Copolymer Structures
Abstract
The morphology of polystyrene/poly(methyl methacrylate) (PS/PMMA) diblock copolymers was investigated as a function of temperature by using small-angle X-ray scattering. It was found that the microphase separation was enhanced up to temperatures in excess of 200 °C. At 175 °C the copolymers remained microphase separated when mixed with PS or PMMA homopolymer at homopolymer concentrations less than 50%, provided the molecular weight of the homopolymer was less than or equal to the total molecular weight of the copolymer. The temperature dependence of the tracer coefficients D⋆HC, of deuteriated polystyrene (d-PS) chains diffusing into two symmetric PS/PMMA diblock copolymers was studied by using forward recoil spectrometry (FRES). D⋆HC/T was found to have the same temperature dependence as D⋆HH/T, where D⋆HHis the tracer diffusion coefficient of d-PS chains diffusing into PS. A comparison of the temperature dependence of the zero-shear rate viscosity, η0, of PS indicates that D⋆HC/T and ηo-1have essentially the same temperature dependence. Experiments on the diffusion of deuteriated poly(methyl methacrylate) (d-PMMA) also indicated that D⋆HC/T and ηo-1 have the same temperature dependence. © 1989, American Chemical Society. All rights reserved.