Abstract
Fundamental understanding of microphase separation in ABC miktoarm copolymers is vital to access a plethora of nonconventional morphologies. Miktoarm stars based on poly(cis 1,4-isoprene) (I), poly(styrene) (S), and poly(2-vinylpyridine) (V) are model systems, which allow systematic studies of the effects of composition, chemical microstructure, and temperature on the thermodynamics of microphase separation. Eleven ISV-x (I:S:V = 1:1:x, v:v:v) miktoarm copolymers were synthesized by anionic polymerization affording well-defined copolymers with a variable V arm. Equilibrium bulk morphologies of all samples, as evidenced by small-angle X-ray scattering, transmission electron microscopy (TEM), and self-consistent field theory, showed a systematic transition from lamellae (x ≈ 0–0.2) to [8.8.4] tiling (x ≈ 0.6–0.9) to cylinders in undulating lamellae (x ≈ 2–4) and, finally, to hexagonally packed core–shell cylinders (x ≈ 5–8). Chemical microstructure of the I arm [poly(cis 1,4-isoprene)] versus poly(3,4-isoprene) is shown to play important role in affecting morphological behavior. To reconcile differences between ISV-x star morphologies reported in the literature and those reported herein, even for the same composition, effects of the microstructure of I arm on the Flory–Huggins parameter between I and V arms were taken into account in a qualitative manner.
| Original language | English |
|---|---|
| Pages (from-to) | 1491-1504 |
| Number of pages | 14 |
| Journal | Journal of Polymer Science, Part B: Polymer Physics |
| Volume | 56 |
| Issue number | 22 |
| DOIs | |
| State | Published - Nov 15 2018 |
Funding
S Chernyy, J J K Kirkensgaard, K Mortensen, and K Almdal are thankful to Villum Foundation for the financial support of the project. Support by the Danish National Research Foundation, Project DNRF103 to K Almdal and L Schulte is acknowledged. Portions of the work including the computations were conducted at the Center for Nanophase Materials Sciences, which is a U.S. Department of Energy Office of Science User Facility. The Research at Oak Ridge National Laboratory’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy (DOE). T P Russell and H Kim were supported by the Air Force Office of Scientific Research under contract 16RT1602. J P Mahalik and M M L Arras were supported by the Laboratory Directed Research and Development, Technology Innovation Program of ORNL managed by UT-Battelle, LLC for the U.S. Department of Energy. S Chernyy, J J K Kirkensgaard, K Mortensen, and K Almdal are thankful to Villum Foundation for the financial support of the project. Support by the Danish National Research Foundation, Project DNRF103 to K Almdal and L Schulte is acknowledged. Portions of the work including the computations were conducted at the Center for Nanophase Materials Sciences, which is a U.S. Department of Energy Office of Science User Facility. The Research at Oak Ridge National Laboratory's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy (DOE). T P Russell and H Kim were supported by the Air Force Office of Scientific Research under contract 16RT1602. J P Mahalik and M M L Arras were supported by the Laboratory Directed Research and Development, Technology Innovation Program of ORNL managed by UT-Battelle, LLC for the U.S. Department of Energy.
Keywords
- ABC miktoarm stars
- bis(phenylethenyl)benzene (1,4-PEB)
- bulk morphology
- phase transition
- poly(2-vinylpyridine) (V)
- poly(isoprene) (I)
- poly(styrene) (S)