Real-time observation on deformation of bicontinuous phase under simple shear flow

The transient shear deformation of phase-separated bicontinuous structures has been investigated by a real time optical microscopy and a small-angle light scattering technique. It is found that, under simple shear flow, the domains are affinely elongated for the shear strain $\gamma >1,$ and the size distribution of the domains is broadened along the flow direction due to the shear-induced coalescence; while in the perpendicular direction, both the average size and the size distribution of the domains remain almost unchanged, but the correlation of the concentration fluctuations is enhanced. The experimental observations are further confirmed by computer simulation.