On Determining Phase Continuity

As reviewed elsewhere,block copolymers may have spherical, cylindrical, or alternating lamellar-type morphologies, with either phase continuous depending on the relative proportions of the two blocks. When the lamellar type of morphology is present, both blocks display a degree of phase continuity. 

While it is still not possible to predict exactly all possible morphologies of polymer blends, blocks, and grafts, the following guidelines may be helpful in relating the synthetic detail to phase continuity.  

For bulk or solution graft copolymerizations, the polymer first synthesized forms the more continuous phase. Polymer II usually forms cellular domains within polymer I. 

Stirring of bulk, suspension, or solution-type graft copolymerizations, especially during the early portion of polymerization II, may cause phase inversion, especially if I is the minority component. 

For emulsion polymerizations, polymer II, tends to form the continuous phase, after subsequent molding or film formation. In general, the molding of shell-core particulates into macroscopic structures leads to greater continuity of the shell component. 

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