Abstract
Bottlebrush polymers, macromolecules consisting of dense polymer side chains grafted from a central polymer backbone, have unique properties resulting from this well-defined molecular architecture. With the advent of controlled radical polymerization techniques, access to these architectures has become more readily available. However, synthetic challenges remain, including the need for intermediate purification, the use of toxic solvents, and challenges with achieving long bottlebrush architectures due to backbone entanglements. Herein, we report hybrid bonding bottlebrush polymers (systems integrating covalent and noncovalent bonding of structural units) consisting of poly(sodium 4-styrenesulfonate) (p(NaSS)) brushes grafted from a peptide amphiphile (PA) supramolecular polymer backbone. This was achieved using photoinitiated electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization in water. The structure of the hybrid bonding bottlebrush architecture was characterized using cryogenic transmission electron microscopy, and its properties were probed using rheological measurements. We observed that hybrid bonding bottlebrush polymers were able to organize into block architectures containing domains with high brush grafting density and others with no observable brushes. This finding is possibly a result of dynamic behavior unique to supramolecular polymer backbones, enabling molecular exchange or translational diffusion of monomers along the length of the assemblies. The hybrid bottlebrush polymers exhibited higher solution viscosity at moderate shear, protected supramolecular polymer backbones from disassembly at high shear, and supported self-healing capabilities, depending on grafting densities. Our results demonstrate an opportunity for novel properties in easily synthesized bottlebrush polymer architectures built with supramolecular polymers that might be useful in biomedical applications or for aqueous lubrication.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 16085-16096 |
| Number of pages | 12 |
| Journal | Journal of the American Chemical Society |
| Volume | 146 |
| Issue number | 23 |
| DOIs | |
| State | Published - Jun 12 2024 |
Funding
This work was primarily supported by the National Science Foundation under grant DMR-2310178. Additional support was provided by the National Science Foundation CHE-2102662 (for NMR spectroscopy studies) and by the Center for Regenerative Nanomedicine at the Simpson Querrey Institute for BioNanotechnology at Northwestern University (for the mechanical testing). T.DC. acknowledges funding support from an American Australian Association Fellowship. We are grateful to the following core facilities at Northwestern University: Peptide Synthesis Core at the Simpson Querrey Institute, supported by the Soft and Hybrid Nanotechnology Experimental (ShyNE) Resource (NSF ECCS \u2013 1542205). The Simpson Querrey Institute, Northwestern University Office for Research, U.S. Army Research Office, and the U.S. Army Medical Research and Materiel Command have also provided funding to develop this facility. Circular dichroism spectroscopy was performed at the Northwestern University Keck Biophysics facility, which is generously supported by an NCI Cancer Center Support Grant (P30 CA060553) awarded to the Robert H Lurie Comprehensive Cancer Center. Electron microscopy experiments were performed at the Electron Probe Instrumentation Center (EPIC) and the BioCryo facility of Northwestern University\u2019s NUANCE Center, which have both received support from the Soft and Hybrid Nanotechnology Experimental (ShyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. NMR and FTIR characterization in this work made use of IMSERC at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (ShyNE) Resource (NSF ECCS-1542205), the State of Illinois, and the International Institute for Nanotechnology (IIN). Rheology experiments made use of the MatCI Facility supported by the MRSEC program of the National Science Foundation (DMR-1720139) at the Materials Research Center of Northwestern University. Portions of this work were performed at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by Northwestern University, The Dow Chemical company, and DuPont de Nemours, Inc. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Cinema 4D illustrations were created by Mark Seniw in the Analytical bioNanoTechnology Equipment Core Facility of the Simpson Querrey Institute for BioNanotechnology at Northwestern University, with partial support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633). Parts of this work were carried out at the Soft Matter Characterization Facility of the University of Chicago and the authors are thankful to the help provided by Philip Griffin in obtaining this data. The authors would like to thank Kristen Wek and Jacob Kupferberg for help with scanning electron microscopy and rheology experiments respectively, and Mark Seniw for his design of Cinema 4D schematic drawings in the manuscript.
ASJC Scopus subject areas
- Catalysis
- General Chemistry
- Biochemistry
- Colloid and Surface Chemistry