The name is absent

mains. With time, these domains coarsen leading to ‘macro-phase’ separation, where
the individual domain sizes are comparable to the volume of the container in which
the fluid is held. The driving force is the interfacial energy of the two phases. Hence
at equilibrium, the interface between the two macro-phases A and B will be minimum
subject to the mass conservation of the species and boundary conditions that reflect
the container. In addition to the two bulk phases, the interfacial region and thereby
the interfacial properties are of fundamental interest.

On the contrary, if the polymers A and B are joined together to form a A-B diblock
copolymer, they can no longer macro-phase separate. Instead, melts of diblock copoly-
mers show an ordering phenomenon known as ‘micro-phase’ separation. At the local
(~ 10 nm) level, A and B blocks phase separate by the same microscopic interactions
that led to macro-phase separation. However, these local domains cannot coarsen
since this would require breaking the bonds between the two blocks of the copolymer
molecules. Indeed, microphase separation of a pure block copolymer melt is more
properly viewed as an ordering phenomenon similar to the crystallization of a one
component molecular fluid, rather than a spatially limited type of phase separation.
Thermodynamic equilibrium corresponds to mesophases consisting of defect-free, pe-
riodic patterns with compositional order in one, two, or three dimensions. Defect
states such as lattice dislocations and grain boundaries, however, are relatively low in
energy and easily populated. Nevertheless, under certain circumstances, it is possible
to obtain mesophases that are nearly defect-free and have a high degree of long-range

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