Abstract
Understanding and precise control of compatibility/incompatibility, networking, and phase separation phenomena between different types of polymers is the key to the creation of recent functional polymers and control of properties, which are indispensable methodologies. In particular, in addition to the temperature responsiveness of polymer solutions, in the intracellular liquid/liquid phase separation of biopolymers and gel-gel phase separation, phenomena caused by phase separation of polymers (aggregation, isolation, self-organization, and the formation of domain interfaces) and its controllability can determine material properties. In this special issue, we will explore advanced polymers using the keyword “phase separation” and provide an opportunity to deepen our understanding of its specificity and usefulness.