skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Graft-through Synthesis and Assembly of Janus Bottlebrush Polymers from A- Branch -B Diblock Macromonomers

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
U.S. AIR FORCE- OFFICE OF SCIENTIFIC RESEARCH
OSTI Identifier:
1346236
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the American Chemical Society; Journal Volume: 138; Journal Issue: 36
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Kawamoto, Ken, Zhong, Mingjiang, Gadelrab, Karim R., Cheng, Li-Chen, Ross, Caroline A., Alexander-Katz, Alfredo, and Johnson, Jeremiah A. Graft-through Synthesis and Assembly of Janus Bottlebrush Polymers from A- Branch -B Diblock Macromonomers. United States: N. p., 2016. Web. doi:10.1021/jacs.6b07670.
Kawamoto, Ken, Zhong, Mingjiang, Gadelrab, Karim R., Cheng, Li-Chen, Ross, Caroline A., Alexander-Katz, Alfredo, & Johnson, Jeremiah A. Graft-through Synthesis and Assembly of Janus Bottlebrush Polymers from A- Branch -B Diblock Macromonomers. United States. doi:10.1021/jacs.6b07670.
Kawamoto, Ken, Zhong, Mingjiang, Gadelrab, Karim R., Cheng, Li-Chen, Ross, Caroline A., Alexander-Katz, Alfredo, and Johnson, Jeremiah A. Wed . "Graft-through Synthesis and Assembly of Janus Bottlebrush Polymers from A- Branch -B Diblock Macromonomers". United States. doi:10.1021/jacs.6b07670.
@article{osti_1346236,
title = {Graft-through Synthesis and Assembly of Janus Bottlebrush Polymers from A- Branch -B Diblock Macromonomers},
author = {Kawamoto, Ken and Zhong, Mingjiang and Gadelrab, Karim R. and Cheng, Li-Chen and Ross, Caroline A. and Alexander-Katz, Alfredo and Johnson, Jeremiah A.},
abstractNote = {},
doi = {10.1021/jacs.6b07670},
journal = {Journal of the American Chemical Society},
number = 36,
volume = 138,
place = {United States},
year = {Wed Sep 14 00:00:00 EDT 2016},
month = {Wed Sep 14 00:00:00 EDT 2016}
}
  • In this study, the synthesis of highly nitrogen-doped mesoporous carbon spheres (NMCS) is reported. The large pores of the NMCS were obtained through self-polymerization of dopamine (DA) and spontaneous co-assembly of diblock copolymer micelles. The resultant narrowly dispersed NMCS possess large mesopores (ca. 16 nm) and small particle sizes (ca. 200 nm). Lastly, the large pores and small dimensions of the N-heteroatom-doped carbon spheres contribute to the mass transportation by reducing and smoothing the diffusion pathways, leading to high electrocatalytic activity.
  • Grafting density and graft distribution impact the chain dimensions and physical properties of polymers. However, achieving precise control over these structural parameters presents long-standing synthetic challenges. In this report, we introduce a versatile strategy to synthesize polymers with tailored architectures via grafting-through ring-opening metathesis polymerization (ROMP). One-pot copolymerization of an ω-norbornenyl macromonomer and a discrete norbornenyl co-monomer (diluent) provides opportunities to control the backbone sequence and therefore the side chain distribution. Toward sequence control, the homopolymerization kinetics of 23 diluents were studied, representing diverse variations in the stereochemistry, anchor groups, and substituents. These modifications tuned the homopolymerization rate constants overmore » two orders of magnitude (0.36 M -1 s -1 < k homo < 82 M -1 s -1). Rate trends were identified and elucidated by complementary mechanistic and density functional theory (DFT) studies. Building on this foundation, complex architectures were achieved through copolymerizations of selected diluents with a poly (D,L-lactide) (PLA), polydimethylsiloxane (PDMS), or polystyrene (PS) macromonomer. The cross-propagation rate constants were obtained by non-linear least squares fitting of the instantaneous co-monomer concentrations according to the Mayo-Lewis terminal model. Indepth kinetic analyses indicate a wide range of accessible macromonomer/diluent reactivity ratios (0.08 < r 1/r 2 < 20), corresponding to blocky, gradient, or random backbone sequences. We further demonstrated the versatility of this copolymerization approach by synthesizing AB graft diblock polymers with tapered, uniform, and inverse-tapered molecular “shapes.” Small-angle X-ray scattering analysis of the self-assembled structures illustrates effects of the graft distribution on the domain spacing and backbone conformation. Collectively, the insights provided herein into the ROMP mechanism, monomer design, and homo- and copolymerization rate trends offer a general strategy for the design and synthesis of graft polymers with arbitrary architectures. Controlled copolymerization therefore expands the parameter space for molecular and materials design.« less