TEMPERATURE AND PRESSURE-DEPENDENCE OF THE ORDER-PARAMETER FLUCTUATIONS, CONFORMATIONAL COMPRESSIBILITY, AND THE PHASE-DIAGRAM OF THE PEP-PDMS DIBLOCK COPOLYMER

Citation
D. Schwahn et al., TEMPERATURE AND PRESSURE-DEPENDENCE OF THE ORDER-PARAMETER FLUCTUATIONS, CONFORMATIONAL COMPRESSIBILITY, AND THE PHASE-DIAGRAM OF THE PEP-PDMS DIBLOCK COPOLYMER, Physical review letters, 77(15), 1996, pp. 3153-3156
Citations number
21
Categorie Soggetti
Physics
Journal title
ISSN journal
00319007
Volume
77
Issue
15
Year of publication
1996
Pages
3153 - 3156
Database
ISI
SICI code
0031-9007(1996)77:15<3153:TAPOTO>2.0.ZU;2-9
Abstract
The structure factor of a poly(ethylene-propylene)-poly(dimethylsiloxa ne) diblock copolymer has been measured by small-angle neutron scatter ing as a function of temperature and pressure. The conformational comp ressibility exhibits a pronounced maximum at the order-disorder phase transition. The phase boundary shows an unusual shape. With increasing pressure it first decreases and then increases. Its origin is an incr ease, respectively, of the entropic and of the enthalpic part of the F lory-Huggins interaction parameter. The Ginzburg parameter describing the limit of the mean-field approximation is not influenced by pressur e.