Post-polymerization modification (PPM) has been broadly employed to achieve functional polymer brush surfaces via immobilization of functional moieties on the brush using efficient organic tranformations. Here, we demonstrate the amine-anhydride reaction as a modular PPM route to functional brush surfaces using poly(styrene–maleic anhydride) (pSMA) copolymer brushes as a platform. The amine-anhydride reaction on pSMA surfaces proceeds to high conversions, with rapid kinetics, under ambient reaction conditions, and exploits a readily available library of functional amines. Using cystamine as a modifier, a convenient route to thiol-functionalized brushes was developed that enables sequential PPM modifications with a large library of alkenes using both base-catalyzed thiol-Michael and radical-mediated thiol–ene reactions. The high fidelity PPM reactions were demonstrated via the development of multifunctional, micropatterned brush surfaces.
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Degradable polyanhydride networks derived from itaconic acid
The development of tunable and degradable crosslinked-polyanhydride networks from renewably derived itaconic anhydrides and multifunctional thiols is presented. Itaconic acid was initially converted to ethyl itaconic anhydride and isoamyl itaconic anhydride via a two-step synthetic procedure on hundred-gram scale with minimal purification. Dinorbornene-functionalized derivatives were prepared via cycloaddition chemistry, and photoinitiated thiol–ene polymerization reactions were explored using commercially available tetra- and hexa-functional thiols, all using solvent-free syntheses. The thiol–ene reaction kinetics of different monomer compositions were characterized by real-time Fourier transform infrared (RT-FTIR) spectroscopy, with the norbornene functionalized derivatives exhibiting the highest reactivity towards thiol–ene photopolymerizations. The thermal and mechanical characteristics of the thermosets were analyzed and the viscoelastic behavior was investigated by dynamic mechanical analysis to understand the influence of the ester functionality and choice of crosslinker on the material properties. The anhydride backbone was found to be susceptible to controlled degradation under physiologically-(phosphate-buffered saline) and environmentally-relevant (artificial seawater) testing conditions over a period of 60 days at 50 °C. This work demonstrates that itaconic acid may be a useful feedstock in the generation of degradable polyanhydride networks via thiol–ene photopolymerization.
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- Award ID(s):
- 1901635
- NSF-PAR ID:
- 10215896
- Date Published:
- Journal Name:
- Polymer Chemistry
- Volume:
- 12
- Issue:
- 4
- ISSN:
- 1759-9954
- Page Range / eLocation ID:
- 608 to 617
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D0PY01388A
