Microphase morphology in two-dimensional fluids under lateral confinement.

We study the effects of confinement between two parallel walls on a two dimensional fluid with competing interactions which lead to the formation of particle microdomains at the thermodynamic equilibrium (microphases or microseparation). The possibility to induce structural changes of the morphology of the microdomains is explored, under different confinement conditions and temperatures. In the presence of neutral walls, a switch from stripes of particles to circular clusters (droplets) occurs as the temperature decreases, which does not happen in bulk. While the passage from droplets to stripes, as the density increases, is a well-known phenomenon, the change of the stripes into droplets as an effect of temperature is rather unexpected. Depending on the wall separation and on the wall-fluid interaction parameters, the stripes can switch from parallel to perpendicular to the walls and also a mixed morphology can be stable.