EQUILIBRIUM ORDER-TO-DISORDER TRANSITION-TEMPERATURE IN BLOCK-COPOLYMERS

The process of order-to-disorder transition (ODT) has been studied in a symmetric diblock copolymer AB and in an asymmetric miktoarm star bl ock copolymer of the AB(3) type. We find that the T-ODT depends on the ordering temperature just as the melting temperature in semicrystalli ne homopolymers depends on the crystallization temperature. In this wo rk we show, for the first time, the existence of an equilibrium transi tion temperature (T-ODT(0)) and we demonstrate how this can be obtaine d. The dependence of the apparent T'(ODT) on the supercooling is attri buted to grains of different sizes. (C) 1998 American Institute of Phy sics. [S0021-9606(98)52115-0].