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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.
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This content will become publicly available on November 17, 2025
Spintronic Pathways in a Nonconjugated Radical Polymer Glass
Abstract Radical chemistries have attracted burgeoning attention due to their intriguing technological applications in organic electronics, optoelectronics, and magneto‐responsive systems. However, the potential of these magnetically active glassy polymers to transport spin‐selective currents has not been demonstrated. Here, the spin‐transport characteristics of the radical polymer poly(4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl) (PTEO) allow for sustained spin‐selective currents when incorporated into typical device geometries with magnetically polarized electrodes. Annealing thin films of PTEO above its glass transition temperature results in a giant magnetoresistance effect (i.e., an MR of ≈80%) at 4 K. Additionally, ferromagnetic resonance spin‐pumping results in a relatively large effective spin‐mixing conductance of 1.18 × 1019m−2at the NiFe/PTEO interface. Due to the large spin‐density and radical‐radical exchange interactions, there is effective propagation of pure spin currents through PTEO in the NiFe/PTEO/Pd multilayer devices. This results in the transport of spin current over long distances with a spin diffusion length of 90.4 nm. The spin diffusion length and spin mixing conductance values surpass those reported in inorganic and metallic systems and are comparable to conventional doped conjugated polymers. This is the first example of spin transport in a nonconjugated radical polymer, and these findings underscore the promising spin‐transporting potential of radical polymers.
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- Award ID(s):
- 2321618
- PAR ID:
- 10555623
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 37
- Issue:
- 3
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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