Thermal composition fluctuations and the associated crossover from the 3D Ising to the isotropic Lifshitz universality class have been studied in a three component mixture made of a critical polymer blend and the corresponding diblock copolymer. The critical exponents were found to be appreciably larger than these of the 3D Ising, in agreement with expectations from the larger upper critical dimension. Very near the critical temperature a crossover to a renormalized Lifshitz critical behavior was observed possibly caused by fluctuation induced rearrangements of the diblock copolymers.
Schwahn, D., Mortensen, K., Frielinghaus, H., & Almdal, K. (1999). Crossover from 3D ising to isotropic Lifshitz critical behavior in a mixture of a homopolymer blend and diblock copolymer. Physical Review Letters, 82(25), 5056-5059. https://doi.org/10.1103/PhysRevLett.82.5056