Transient solidlike behavior near the cylinder/disorder transition in block copolymer solutions
Park, MJ; Char, K; Lodge, TP; Kim, JK
HERO ID
1315355
Reference Type
Journal Article
Year
2006
Language
English
PMID
| HERO ID | 1315355 |
|---|---|
| In Press | No |
| Year | 2006 |
| Title | Transient solidlike behavior near the cylinder/disorder transition in block copolymer solutions |
| Authors | Park, MJ; Char, K; Lodge, TP; Kim, JK |
| Journal | Journal of Physical Chemistry B |
| Volume | 110 |
| Issue | 31 |
| Page Numbers | 15295-15301 |
| Abstract | A nearly symmetric polystyrene-block-polyisoprene diblock copolymer dissolved at a concentration of 40% in styrene-selective solvents exhibited a cylinder-to-disorder transition upon heating. The solvents used were diethyl phthalate (DEP) and 75:25 and 50:50 mixtures of DEP with di-n-butyl phthalate (DBP). In DEP, the most styrene-selective of the three solvents, rheological measurements indicated a distinct plateau in the temperature-dependent elastic modulus across the 8 degrees C interval above the order-disorder transition temperature, T(ODT) = 116 degrees C. Previous small-angle neutron scattering measurements in this regime indicated the equilibrium phase to be a liquidlike solution of approximately spherical micelles. An isothermal frequency sweep in this regime indicated a very long relaxation time. Annealing eventually led to the recovery of liquidlike rheological response, over a time scale of hours. Qualitatively similar phenomena were also observed in 75:25 DEP/DBP and 50:50 DEP/DBP solutions, except the fact that the temperature window of the transient response is narrow and the time scale for the recovery diminishes significantly. Neither small-angle X-ray scattering nor static birefringence gave any clear signature of the transient structure. The structure that leads to the transient rheological response is attributed to micellar congestion due to the slow relaxation of anisotropic micelles into an equilibrium distribution of micelles. Possible origins of the remarkable solvent selectivity dependence are also discussed. |
| Doi | 10.1021/jp056336i |
| Pmid | 16884248 |
| Wosid | WOS:000239463300037 |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Scopus URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748268716&doi=10.1021%2fjp056336i&partnerID=40&md5=6ee29abf0d5afa6e73adb8ce7fdce8cd |
| Is Public | Yes |
| Language Text | English |