Engineering nanophase self-assembly with elastic field

A binary monolayer on an elastic substrate may separate into two phases, which self-assemble into ordered nanoscale patterns. We apply an elastic field to the substrate to guide the self-assembly process. The effect of arbitrary three-dimensional external loading is found to be characterized by a single two-dimensional parameter – a surface stain field of the substrate. A non-uniform strain field significantly influences the size, shape and orientation of self-assembled features, and may induce the formation of pattern colonies. It is shown that a pattern orientates normal to the strain gradient direction. An applied load anchors the position of a self-assembled pattern relative to the substrate, where a colony boundary resides on the strain gradient region. The work suggests a method of strain field design to make various monolayer patterns for nanofabrication.