Strong segregation limit

Monte Carlo simulations, which include fluctuations, then yields Simulations of a coarse-grained polymer blend by Wemer et al find = 1 [49] in the strong segregation limit, in rather good... 

Recently, Grason and Kamien calculated the phase diagrams in the weak and strong segregation limit for AB miktoarm-star copolymers using both... 

Fig. 36 SCFT results for AB miktoarm stars at strong segregation limit /W = 100. Phase transitions (A) Dis bcc-, (o) bcc Hex-, (0) Hex Lam. All boundaries are computed at /N = 100 with exception of low-0 bcc - Hex and Hex Lam ones for n = 3, 4 and 5. For n = 3 these were computed at /AT = 80, and for n = 4 and 5 these boundaries are computed at /N = 60. Equilibrium results from experiments on Pl-arm-PS melts [219]. From [112]. Copyright 2004 American Chemical Society...

Usually the discussion of the ODT of highly asymmetric block copolymers in the strong segregation limit starts from a body-centred cubic (bcc) array of the minority phase. Phase transitions were calculated using SOFT accounting for both the translational entropy of the micelles in a disordered micelle regime and the intermicelle free energy [129]. Results indicate that the ODT occurs between ordered bcc spheres and disordered micelles. 

Fig. 2.1 Composition profiles of A and B components in the weak and strong segregation limits, compared to the mean (straight line).

Fig. 2.34 Phase diagram in the strong segregation limit for starblock copolymers with nA A arms and nB B arms as a function of the volume fraction of the B monomer (Milner 1994).

Fig. 2.38 Phase diagram computed using the strong segregation limit theory of Helfand and Wasserman (1982) for the poly(ethylene oxide)-poly(butylene oxide) (PEO-PBO) diblock system. Because the ratio of statistical segment lengths aPB0/ 1, the phase diagram is asymmetric about/= 0.5 (Hamley 1997).

A mean field approach was applied to determine homopolymer distributions in the lamellar phase of a blend of AB diblock and A homopolymer by Shull and Winey (1992). In the strong segregation limit, complete segregation of the A homopolymer into the A microdomain was predicted. Furthermore, in this limit, the diblocks were treated as brushes , wetted by homopolymer in the A domain. Composition profiles showing the distribution of homopolymer and copolymer were determined by numerical solution of the self-consistent field equations. 

The stabilization of bicontinuous phases by addition of homopolymer to diblocks was studied in the strong segregation limit by Xi and Milner (19%).They found that a bicontinuous cubic structure (presumably the gyroid phase) is stable for 0,56 < f < 0.68, with corresponding optimal volume fractions of homopolymer ranging from 0.18 to 1.00 for this range of/. 

Similar calculations were also performed in the strong segregation limit. In this case, the two-phase and disordered homogeneous regions were found to be smaller, and the phase boundaries were more vertical (see Fig. 6.49) (Shi and Noolandi 1995). This phase diagram was interpreted on the basis of interfacial curvature. If the diblocks are completely segregated, the phase boundaries are determined by the total composition / (=

phase boundaries are parallel to this line (dashed line sloping to the left in Fig. 6.49) ( one-component approximation ). This explains the approximately parallel... 

In this review, we introduce another approach to study the multiscale structures of polymer materials based on a lattice model. We first show the development of a Helmholtz energy model of mixing for polymers based on close-packed lattice model by combining molecular simulation with statistical mechanics. Then, holes are introduced to account for the effect of pressure. Combined with WDA, this model of Helmholtz energy is further applied to develop a new lattice DFT to calculate the adsorption of polymers at solid-liquid interface. Finally, we develop a framework based on the strong segregation limit (SSL) theory to predict the morphologies of micro-phase separation of diblock copolymers confined in curved surfaces. 

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