Phase separation of block copolymer

More recently, many studies have been reported on the micro-phase separation of block copolymers with multidimensional confinements including cylindrical and spherical shapes. Shin and Xiang s group (Shin et al., 2004 Xiang et al., 2004 Xiang et al., 2005a) observed the... 

Despite these successes, molecular modelling will never be able to address phenomena, which involve length scales of hundreds of nanometers and more, such as the phase separation of block-copolymers, or very long timescales, such as mechanical properties related to sub Tg relaxations. Therefore more and more effort is devoted to the development of mesoscale models linked in a well defined way to the atomic level. 

As with phase separation of block copolymers in bulk, the nature and size of the aggregates formed in a block-selective solvent depends on the relative sizes of the two blocks as well as the overall molecular weight of the diblock copolymer. In... 

E.g., in polymer chemistry phase separation of block copolymers or the formation of defined micelles is being used (3-10). 

The practical synthesis of hierarchical networks can be achieved in various ways quite commonly colloid particles are used for templating the macropores, while meso- and micropores can be introduced by phase separation of block copolymers or surfactants. 

The phase separation of block copolymers in bulk is also the driving force for their self-assembly. Self-assembly of amphiphilic block copolymers in specific solvents leads to a vast variety of aggregates where functionality can be compartmentalized like in micelles and various types of vesicles like polymersomes (Fig. 5.5a). The type of vesicle formed depends on the hydro-phobic/hydrophilic ratio and the block length of the block copolymers (Fig. 5.9 see also Section 6.1). Different functionalities, like a metal binding group, complexation units, bioactive groups, or pH or salt concentration-sensitive units, can then be placed selectively into one of the phases, for example, at the inner part of a micellar structure or in the corona. 

Figure 4. Schematic representations of five types of microstructures for phase separation of block copolymer as a function of composition [55].

Yu, K., Wang, H., Han, Y. (2007). Motion of integrated CdS nanoparticles by phase separation of block copolymer brushes. Langmuir, 23, 8957-8964. 

Instead of the MC and MD methods using explicit particles, another method, that is, polymeric self-consistent field theory (SCFT) proposed by Edwards, is often used to study the phase separation of block copolymers. In SCFT, a polymer chain is treated as a Gaussian string, which is exposed to a set of effective chemical potentials ( ). The chemical potentials are used instead of the actual interactions between different components. Importantly, the relation between the external potentials and the concentration field ((/>) is bijective. 

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