Structure development in multi-block copolymerisation: Comparison of experiments with cell dynamics simulations

A cell dynamics simulation of phase separation in block copolymers is compared with experimental observations for two related systems, polyurethane (poly(ether-urea)) foam and poly(ether-isocyanurate). Time resolved SAXS measurements on both systems suggest a spinodal-like mechanism with kinetics following a time-dependent Ginzburg-Landau (TDGL) model. TEM micrographs from a range of sources show reactively processed multi-block copolymers to have a bicontinuous morphology, which is discussed as a non-equilibrium relic of the phase separation process. A TGDL based cell-dynamics model gives predictions of the morphology, which can be compared to TEM images and SAXS patterns. The model does not contain any reactive aspects but captures the morphology of the systems which both showed pinning of the micro-structure at early stages of microphase separation in contrast to the equilibrium structures formed by block copolymers.