Our paper “Instability of the Microemulsion Channel in Block Copolymer-Homopolymer Blends” has now been published in the prestigious journal Physical Review Letters and is available here. The work is a collaboration between the University of Waterloo in Canada and Lincoln.

Instability of the Microemulsion Channel in Block Copolymer-Homopolymer Blends

Bart Vorselaars, Russell K. W. Spencer, and Mark W. Matsen Phys. Rev. Lett. 125, 117801 – Published 10 September 2020

Abstract: Field theoretic simulations are used to predict the equilibrium phase diagram of symmetric blends of AB diblock copolymer with A- and B-type homopolymers. Experiments generally observe a channel of bicontinuous microemulsion (BμE) separating the ordered lamellar (LAM) phase from coexisting homopolymer-rich (A+B) phases. However, our simulations find that the channel is unstable with respect to macrophase separation, in particular, A+B+BμE coexistence at high T and A+B+LAM coexistence at low T. The preference for three-phase coexistence is attributed to a weak attractive interaction between diblock monolayers.