SOLUTION PROPERTIES OF DIBLOCK COPOLYMERS OF POLYSTYRENE-BLOCK-POLYBUTADIENE

A combination of transmission electron microscopy (TEM), dynamic light scattering (DLS), static light scattering (SLS), and flow field-flow fractionation (flow-FFF) techniques were, used to study the solution b ehavior of diblock copolymers of polystyrene-block-polybutadiene in he xane. Results obtained from all these techniques showed that the diblo ck copolymer forms micelles in selective solvents, Analysis via DLS in dicates that, in hexane, the micelles have a hydrodynamic diameter (D- h) of similar to 140 nm. It was also found that each micelle is compos ed of a few hundred polymer molecules. Mow FFF was used to analyze the diblock copolymer in hexane and in a solution of hexane and ethylbenz ene. The data obtained via flow FFF show the presence of both single p olymer molecules and micelles, It was also observed that, upon titrati on of a diblock copolymer solution in hexane by ethylbenzene, the mice lles started to dissolve, and at 23% ethylbenzene the micelles complet ely dissolved. Moreover, the diblock copolymer solution in hexane was titrated with styrene, and the effect of the micellar structure was st udied by both dynamic light scattering (DLS) and static light scatteri ng (SLS).