  Using the delta correction to the standard free energy \cite{bc} in the
elastic setting with a quadratic foundation term and some parameters, we
introduce a one dimension only model for strong segregation in diblock
copolymers, whose sharp interface periodic microstructure is consistent with
experiment in low temperatures. The Green's function pattern forming
nonlocality is the same as in the Ohta-Kawasaki model. Thus we complete the
statement in [31,p.349]: ``The detailed analysis of this model will be given
elsewhere. Our preliminary results indicate that the new model exhibits
periodic minimizers with sharp interfaces.'' We stress that the result is
unexpected, as the functional is not well posed, moreover the instabilities in
$L^2$ typically occur only along continuous nondifferentiable ``hairs''.
  We also improve the derivation done by van der Waals and use it and the above
to show the existence of a phase transition with Maxwell's equal area rule.
However, this model does not predict the universal critical surface tension
exponent, conjectured to be 11/9. Actually, the range $(1.2,1.36)$ has been
reported in experiments [21,p. 360]. By simply taking a constant kernel, this
exponent is 2. This is the experimentally ($ \pm 0.1$) verified tricritical
exponent, found e.g., at the consolute $0.9$ K point in mixtures of ${}^3$He
and ${}^4$He. Thus there is a third unseen phase at the phase transition point.
