PRESSURE-DEPENDENCE OF THE ORDER-DISORDER TRANSITION IN SEVERAL DIBLOCK COPOLYMERS STUDIED WITH SANS

Thermal composition fluctuations in three diblock copolymers were stud ied with SANS as a function of temperature and pressure (0.1-200 MPa). In all cases the phase diagram shows an unusual shape insofar as with increasing pressure the order disorder temperature T-ODT first decrea ses and then increases. The pressure induced changes of T-ODT are caus ed by the increase of the enthalpic and entropic terms of the Flory-Hu ggins parameter. (C) 1998 Elsevier Science B.V. All rights reserved.