(513d) The Effect of Polymer Structure and Solvent Selectivity On Ordering Kinetics in Solution Cast Block Copolymer Films

The kinetics of ordering in solution cast block copolymer films has been studied using a novel in situ small-angle X-ray scattering technique. By tracking changes in the scattering intensity as solvent is continually removed from the film, information on the ordering rate was obtained as the film progresses from the dilute to the concentrated regime.  The ordering rate has been found to be controlled by thermodynamics below a critical concentration and by limited chain mobility at higher concentrations. Previous work in our group has considered the effects of temperature, sweep gas and solvent saturation on the ordering kinetics of a polystyrene-b-polybutadiene (SB) diblock copolymer that forms hexagonally packed cylinders in a neutral solvent (toluene.) The effect on ordering kinetics of changes in solvent selectivity and drying rate in the same polymer system and a closely related triblock copolymer system (SBS) are now reported.  In addition, the effect of adding butadiene-selective and styrene-selective tackifying agents will be discussed.  Finally, the ordering kinetics of a polymethylmethacrylate-b-polybutylacrylate (PMMA-PBA) triblock copolymer system with varying PMMA to PBA ratios, resulting in different ordered phase morphologies, is presented.