Copolymer phase diagram

Khandpur A.K., Eoerster S., Bates E.S., Hamley I.W., Ryan A.J., Bras W., Almdal K., and Mortensen K. Polyisoprene-polystyrene diblock copolymer phase diagram near the order-disorder transition. Macromolecules, 28, 8796, 1995. 

Khandpur AK, Forster S et al (1995) Polyisoprene-polystyrene diblock copolymer phase diagram near the order-disorder transition. Macromolecules 28 8796-8806... 

Fig. 4.4 Theoretical diblock copolymer phase diagrams for different levels of polydispersity. a An increase of the overall PDI with identical block PDIs results in a shift towards lower xA values while the phase diagram stays symmetrical (Adapted with permission from Cooke et al. [20]. Copyright 2013 American Chemical Society), b An asymmetrical increase of PDI with PD/a > PDIs shifts the phase boundaries towards decreasing xA and increasing /a values, and creates biphasic regions 2-4>. Note that the phase space of the pure gyroid morphology is even narrower for asymmetric block polydispersities (Reprinted with permission from Matsen et al. [21]. Copyright 2013 by the American Physical Society)...

G. Floudas, B. Vazaiou, F. Schipper, R. Ulrich, U. Wiesner, H. latrou and N. Hadjichristidis, Poly(ethylene oxide-b-isoprene) Diblock Copolymer Phase Diagram, Macromolecules 34 2947 (2001). 

Figure 2.4 Diblock copolymer phase diagram parameterized by / and xN, calculated by Cochran et al Reproduced with permission from Ref. [6].

To estabhsh relationships between different block copolymer phase diagrams and also to facilitate comparison with theory, it is necessary to specify parameters in addition to yN and/. First, asymmetry of the conformation... 

Figure 16 Theoretical mean-field diblock copolymer phase diagram. The arrows indicate the strong segregation constant composition limits between C/S and L/C. Reproduce from Matsen, M. W. In Soft Condensed Matter Gompper, G. Schick M., Eds. Wiley-VCH Weinheim, 2006 Vol. 1, pp 1-84. Matsen, M.W. Schick, M. Phys. Rev. Lett. 1994, 72,...

Although all copolymer phase diagrams are qualitatively similar, they vary quantitatively from copolymer to copolymer, and they are generally not perfectly symmetric about /a = 0.5. The small differences in phase diagrams for different molecules of the same architectures, for example, diblock PS-PI versus diblock PS-PDB, can thus be characterized in terms of different conformational asymmetries of the polymers. 

In a dilute solution, blends of homopolymers A and B equivalent to the two blocks of the copolymers are compatible in a common good solvent contrary to what happens in a highly selective solvent, we do not expect mesophases to form in a dilute solution but only in semidilute and concentrated solutions. Mesophases formed by block copolymers in nonselective solvents have been studied many experimental groups, perhaps most recently bv Hashimoto et al. and Williams et al. The usual interpretation of experiments is based on the "dilution approximation" in which the phase diagram of a solution can be obtained from the corresponding pure copolymer phase diagram by replacing Xab AB where is the monomer volume fraction. We have seen in section... 

Shi A-C, Noolandi J. Binary mixtures of diblock copolymers. Phase diagrams with a new twist. Macromolecules 1995 28 3103-9. 

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