Block polymer self-assembly typically translates molecular chain connectivity into mesoscale structure by exploiting incompatible blocks with large interaction parameters (χij). In this article, we demonstrate that the converse approach, encoding low-χ interactions in ABC bottlebrush triblock terpolymers (χAC ≤ 0), promotes organization into a unique mixed-domain lamellar morphology, which we designate LAMP. Transmission electron microscopy indicates that LAMP exhibits ACBC domain connectivity, in contrast to conventional three-domain lamellae (LAM3) with ABCB periods. Complementary small-angle X-ray scattering experiments reveal a strongly decreasing domain spacing with increasing total molar mass. Self-consistent field theory reinforces these observations and predicts that LAMP is thermodynamically stable below a critical χAC, above which LAM3 emerges. Both experiments and theory expose close analogies to ABA' triblock copolymer phase behavior, collectively suggesting that low-χ interactions between chemically similar or distinct blocks intimately influence self-assembly. These conclusions provide fresh opportunities for block polymer design with potential consequences spanning all self-assembling soft materials.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jun 20 2017|
Bibliographical noteFunding Information:
The authors thank M. S. Ladinsky for assistance with ultramicrotomy, as well as M. T. Irwin, S. Chanpuriya, and T. Li for helpful discussions about sample preparation and TEM. The authors gratefully acknowledge helpful discussions with F. S. Bates and Z.-G. Wang. This work was supported by the National Science Foundation through Grant CHE-1502616. A.B.C. thanks the US Department of Defense for support through the National Defense Science and Engineering Graduate (NDSEG) Fellowship. C.M.B. thanks the Dreyfus Foundation for Environmental Postdoctoral Fellowship EP-13-142 and the University of California, Santa Barbara for funding. This research used resources of the Advanced Photon Source, a US Department of Energy Office of Science User Facility operated by Argonne National Laboratory under Contract DE-AC02-06CH11357.
- Block polymer
- Domain spacing
- Polymer nanostructure