Nanophase separation of small and large molecules

Phase separation on a macroscopic scale is a basic phenomenon which is thermodynamically well understood. A decrease in the size of the phases to micrometer dimensions leads to microphase-separated, colloidal systems that are strongly influenced by surface properties. In this paper the logical extension of phase separation to nanometer dimensions is explored on hand of selected experiments on small and large molecules. Recently discovered macromolecules which consist of short, alternating, incompatible chain segments can be understood better when recognizing that the incompatible segments undergo nanophase separation. One or both of these phases may show positional and/or conformational disorder when close packing across the interface is not possible.