Combining photocontrolled-cationic and anionic-group-transfer polymerizations using a universal mediator: enabling access to two- and three-mechanism block copolymers
Title: Combining photocontrolled-cationic and anionic-group-transfer polymerizations using a universal mediator: enabling access to two- and three-mechanism block copolymers
The first example of poly(vinyl ether)-block-poly(thiirane)-block-poly(acrylamide) from sequentially combining photocontrolled cationic, thioacyl anionic group transfer, and radical polymerization with no intermediate end-group manipulation steps. more »« less
A block copolymer with the structure ethylcellulose-block-poly(benzy glutamate) was synthesizedviaring-opening polymerization and used as a compatibilizer to produce blends of ethylcellulose and poly(ethylene terephthalate).
Mann, Arielle; Hannigan, Matthew D.; Weck, Marcus
(, Macromolecular Chemistry and Physics)
Abstract Poly(p‐phenylene vinylene)s (PPVs) and poly(arylene vinylene)s are key materials for a variety of applications ranging from organic light emitting diodes to fluorescent optical probes. Their syntheses, however, have been hampered by non‐living or step‐growth polymerization techniques. The development of functional‐group tolerant olefin metathesis catalysts has enabled the use of living ring‐opening metathesis polymerization (ROMP) of cyclophane monomers yielding PPVs and poly(p‐phenylene‐co‐arylene vinylene)s in a living manner. Low dispersity and soluble PPVs are afforded with control over the number of repeat units with easy incorporation of different end‐groups at their heads or tails. In this review, a comprehensive overview of tetrasubstituted and disubstituted alkyl and alkoxy containing [2.2]paracyclophane‐1,9‐diene, [2.2]metaparacyclophane‐1,9‐diene, [2.2.2]paracyclophane‐1,9,17‐triene, and benzothiadiazole‐[2.2]paracyclophane‐1,9‐diene is provided. The high ring strain of these monomers enables efficient polymerizations with ruthenium initiators. A particular emphasis is on [2.2]paracyclophane‐1,9‐dienes as it is the most investigated class of polymerized cyclophanediene since initially reported 30 years ago. Additionally, applications for soft materials synthesized by ROMP are examined, highlighting easily accessed PPV copolymers and PPV block copolymers that can be phototriggered, as well as PPVs featuring supramolecular recognition units installed at their termini to afford orthogonally self‐assembled architectures.
Abstract The effect of vortex‐induced mechanical stresses on the fluorescent properties of dye‐containing poly(ethylene glycol)‐block‐poly(lactic acid) (PEG‐b‐PLA) block copolymer micelles has been investigated. PEG‐b‐PLA block copolymer micelles containing fluorescent dyes, 3,3′‐dioctadecyloxacarbocyanine perchlorate (DiO) and/or 1,1′‐dioctadecyl‐3,3,3′,3′‐tetramethylindocarbocyanine perchlorate (DiI), are prepared by a simple one‐step procedure that involves the self‐assembly of block copolymers and spontaneous incorporation of hydrophobic dyes into the core of the micelles. Upon vortexing, the micelle dispersion samples showed a decrease in fluorescence intensity in a rotational speed‐ and time‐dependent manner. The results demonstrated that the vortexing can alter the fluorescent properties of the dye‐containing PEG‐b‐PLA block copolymer micelle dispersion samples, suggesting the potential utility of block copolymer micelles as a mechanical stress‐responsive nanomaterial.
Mei, Shan; Wilk, Jeffrey T.; Chancellor, Andrew J.; Zhao, Bin; Li, Christopher Y.
(, Macromolecular Rapid Communications)
Abstract Block copolymer brushes are of great interest due to their rich phase behavior and value‐added properties compared to homopolymer brushes. Traditional synthesis involves grafting‐to and grafting‐from methods. In this work, a recently developed “polymer‐single‐crystal‐assisted‐grafting‐to” method is applied for the preparation of block copolymer brushes on flat glass surfaces. Triblock copolymer poly(ethylene oxide)‐b‐poly(l‐lactide)‐b‐poly(3‐(triethoxysilyl)propyl methacrylate) (PEO‐b‐PLLA‐b‐PTESPMA) is synthesized with PLLA as the brush morphology‐directing component and PTESPMA as the anchoring block. PEO‐b‐PLLA block copolymer brushes are obtained by chemical grafting of the triblock copolymer single crystals onto a glass surface. The tethering point and overall brush pattern are determined by the single crystal morphology. The grafting density is calculated to be ≈0.36 nm−2from the atomic force microscopy results and is consistent with the theoretic calculation based on the PLLA crystalline lattice. This work provides a new strategy to synthesize well‐defined block copolymer brushes.
Abstract Durable and conductive interfaces that enable chronic and high‐resolution recording of neural activity are essential for understanding and treating neurodegenerative disorders. These chronic implants require long‐term stability and small contact areas. Consequently, they are often coated with a blend of conductive polymers and are crosslinked to enhance durability despite the potentially deleterious effect of crosslinking on the mechanical and electrical properties. Here the grafting of the poly(3,4 ethylenedioxythiophene) scaffold, poly(styrenesulfonate)‐b‐poly(poly(ethylene glycol) methyl ether methacrylate block copolymer brush to gold, in a controlled and tunable manner, by surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) is described. This “block‐brush” provides high volumetric capacitance (120 F cm─3), strong adhesion to the metal (4 h ultrasonication), improved surface hydrophilicity, and stability against 10 000 charge–discharge voltage sweeps on a multiarray neural electrode. In addition, the block‐brush film showed 33% improved stability against current pulsing. This approach can open numerous avenues for exploring specialized polymer brushes for bioelectronics research and application.
Hosford, Brandon M, Ramos, William, and Lamb, Jessica R. Combining photocontrolled-cationic and anionic-group-transfer polymerizations using a universal mediator: enabling access to two- and three-mechanism block copolymers. Retrieved from https://par.nsf.gov/biblio/10590005. Chemical Science 15.33 Web. doi:10.1039/d4sc02511c.
Hosford, Brandon M, Ramos, William, & Lamb, Jessica R. Combining photocontrolled-cationic and anionic-group-transfer polymerizations using a universal mediator: enabling access to two- and three-mechanism block copolymers. Chemical Science, 15 (33). Retrieved from https://par.nsf.gov/biblio/10590005. https://doi.org/10.1039/d4sc02511c
Hosford, Brandon M, Ramos, William, and Lamb, Jessica R.
"Combining photocontrolled-cationic and anionic-group-transfer polymerizations using a universal mediator: enabling access to two- and three-mechanism block copolymers". Chemical Science 15 (33). Country unknown/Code not available: Chem. Sci.. https://doi.org/10.1039/d4sc02511c.https://par.nsf.gov/biblio/10590005.
@article{osti_10590005,
place = {Country unknown/Code not available},
title = {Combining photocontrolled-cationic and anionic-group-transfer polymerizations using a universal mediator: enabling access to two- and three-mechanism block copolymers},
url = {https://par.nsf.gov/biblio/10590005},
DOI = {10.1039/d4sc02511c},
abstractNote = {The first example of poly(vinyl ether)-block-poly(thiirane)-block-poly(acrylamide) from sequentially combining photocontrolled cationic, thioacyl anionic group transfer, and radical polymerization with no intermediate end-group manipulation steps.},
journal = {Chemical Science},
volume = {15},
number = {33},
publisher = {Chem. Sci.},
author = {Hosford, Brandon M and Ramos, William and Lamb, Jessica R},
}
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