Bulk microphase separation characteristics

Beyond a characteristic temperature Todt [14,20], diblock copolymers self-assemble into microphase-separated morphologies. The theoretically predicted equilibriiun states of such ordered phases correspond to perfect superlattices with various symmetries depending on the volume ratio of both blocks. In particular, lamellar (synunetric diblocks), cylindrical (asymmetric diblocks), and spherical (strongly asynunetric diblocks) morphologies are expected and have been observed [2], For typical copolymers, the characteristic length scale of these microphases is in the range from about lOnm up to some 100 nm. It is justified to say that in the bulk, microphase-separated block-copolymers represent ordered nano-structures. 

Predicting the characteristic sizes and morphologies of these nanostructures has been an intense topic of investigation from both the theoretical and experimental points of view. Critical parameters are the degree of polymerization and the volume fraction of the constituent blocks, as well as the Flory-Huggins parameter between them. More complete information about microphase separated structures in bulk block copolymers can be found in the book of Hamley [2],... 

Because of the basic thermodynamic incompatibility of the segments, localized microphase separation occurs, leading to the well recognized domain structure, and the properties of the final bulk material are strongly influenced by the extent of microphase separation and by the morphological characteristics of the domains (Fig. 

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