for mixtures of different diblock copolymers with overall composition $\phi$ [@ARB90] in the strong segregation limit, in which the entropy of mixing of such different copolymers would be negligible

Free energies of classical diblock topologies {#sec:classical}
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Round unit cells
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Using the results of Section \[sec:2a\] we can find the energies of the classical phases of diblock-copolymers: lamellae (L), cylinders (C), and spheres (S) in the round unit cell approximation, in which the unit cells are taken to consist of identical wedges. The corresponding free energies are: $$\begin{aligned}
{f_{lam} \over f_0} &=& \left[\varepsilon(1-\phi) +
{\phi\over\varepsilon}\right]^{1/3} \label{eq:felam}\\
{f_{cyl} \over f_0} &=& \left[ 
{2 \varepsilon\phi(1-\phi^{1/2})^3(3+\phi^{1/2})
\over (1-\phi)^2} + {2 \phi \over \varepsilon}\right]^{1/3} \label{eq:fecyl} \\
{f_{sph} \over f_0} &=& 3\left[ {\varepsilon\phi^{4/3}(1-\phi^{1/3})^3
(\phi^{2/3}+3\phi^{1/3}+6) \over 10(1-\phi)^2} +
{\phi \over 10\varepsilon} \right]^{1/3}\!\!\!\!\!\!\!. \label{eq:fesph}\end{aligned}$$

Calculations based on round unit cells [@semenov85] provide lower bounds for the free energy, because they in fact describe the free energy per molecule of micelles.[@olmsted94a] We may imagine a volume packed with such micelles, the interstitial regions filled with compatible long homopolymer with negligible surface tension against the outsides of the micelles, and negligible entropy of mixing. Then we could do work to deform the micelles into a space-filling array, expelling 