Morphological Behavior of Compositionally Gradient Polystyrene–Polylactide Bottlebrush Copolymers
- Univ. at Buffalo, The State Univ. of New York, Buffalo, NY (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
Morphological behavior of PS–PLA bottlebrush copolymers with a compositional gradient along the backbone was investigated by small-angle X-ray scattering (SAXS) analysis and compared to that of their block copolymer analogs. Side chain-symmetric gradient copolymers with varying volume fractions were prepared by one-step ring-opening metathesis polymerization of the corresponding exo- and endo-norbornene-functionalized macromonomers of similar lengths. The morphological map constructed using the SAXS data revealed a wide cylindrical morphology window, including for symmetric compositions, well-ordered lamella morphologies at very low PS volume fractions, and the formation of a rare bicontinuous gyroid morphology. In addition to the highly asymmetric nature of the morphology diagram, the domain spacings obtained for gradient bottlebrush copolymers were significantly smaller (by 30–40%) than the corresponding bottlebrush block copolymer analogs, which was attributed to a nonperpendicular orientation of the gradient bottlebrush backbone at the domain interface. Side chain-asymmetric gradient bottlebrush copolymers were synthesized from PS and PLA macromonomers of different lengths and were demonstrated to assemble into well-ordered cylindrical and lamella morphologies. The results of these studies demonstrate that the gradient interface plays an important role in determining molecular packing during bottlebrush copolymer self-assembly. As a result, a rich morphological behavior of the gradient bottlebrush copolymers combined with their “user-friendly” one-step synthesis provides a robust and versatile platform for nanostructured material-design and fabrication.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
- Grant/Contract Number:
- SC0012704; DMR-1709371; DMR-0520547; 654000
- OSTI ID:
- 1579894
- Report Number(s):
- BNL-212415-2019-JAAM
- Journal Information:
- Macromolecules, Vol. 52, Issue 21; ISSN 0024-9297
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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