Test of the Leibler theory

First studies addressed the transition of symmetrical block copolymers (/ = N +Ni — 2) disordered melt to the lamellar mesophase (Fig. 

cfioosing the model of Fig. 7.16 (see Section 7.2.5 for a discussion) and focusing attention on the collective structure factor (Fig. 7.20[a]). According to the Leibler theory it has the explicit form 

As will be discussed in the next section, the shift of tf with increasing eN (Fig. 7.20) can be interpreted as resulting from an onset of chain stretching. While experimentally it was suggested that the transition from Gaussian coils to stretched chains that occurs at a temperature T above Tc is rather sharp, the more complete simulation data on this point show that this stretching of the chains sets in very gradually. 

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