Disorder-Order Transition and Nanostructure Control in a Polystyrene-b-Poly(ethyl methacrylate) DiBlock Copolymer

Abstract

The phase behaviour of a diblock copolymer based on poly(styrene) and poly(ethyl methacrylate) is studied in the weak segregation limit. The unmixing of the blocks into a lamellar morphology takes place during heating and the ordering transition (LDOT) is located around 160 ºC. Fine control of the inter-layers thickness in the lamellar phase is achieved by annealing with time-temperature dependence above the LDOT. The irreversibility of the nanophase separation makes possible the freezing of the layered structure into room temperature. Therefore, we present a simple way to produce a diblock copolymer with a layered structure controlling on demand the size of the inter-layers spacing in a wide range from 35 up to 48 nm.