| Autor: |
Sugiyama, M., Shefelbine, T. A., Vigild, M. E., Bates, F. S. |
| Zdroj: |
The Journal of Physical Chemistry - Part B; December 2001, Vol. 105 Issue: 50 p12448-12460, 13p |
| Abstrakt: |
The structures of ternary blends composed of a nearly symmetric poly(styrene-b-isoprene-b-dimethylsiloxane) (SID) triblock copolymer (volume fractions of S/I/D = 0.20/0.59/0.21, Mn = 40 000 g/mol) and equal volume fractions of low-molecular-weight polystyrene (Mn = 2360 g/mol) and poly(dimethylsiloxane) (Mn = 2200 g/mol) are investigated by small-angle X-ray and neutron scattering and transmission electron microscopy. When the total homopolymer volume fraction exceeds 65%, the blend macroscopically separates into ordered homopolymer-poor and -rich regions. Between 45 and 65% homopolymer volume fraction, hexagonally packed core−shell cylinders form with PDMS cores and PI shells. Between 15 and 45% homopolymer volume fraction, a core−shell gyroid morphology is observed with PDMS cores and PI shells. These core−shell variations of the classical structures of diblock copolymers are attributed to a small asymmetry in segment−segment interaction parameters. The neat SID block copolymer has a new complex ordered microstructure. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
