Tunable pH-and CO2-Responsive Sulfonamide-Containing Polymers by RAFT Polymerization
Document Type
Article
Publication Date
8-25-2015
Department
Polymers and High Performance Materials
Abstract
The controlled RAFT polymerization of a library of pH- and CO2-responsive methacryloyl sulfonamides (MSAs) that possess pKa values in the biologically relevant regime (pH = 4.5–7.4) is reported. Initial polymerizations were conducted at 70 °C in DMF with 4-cyano-4-(ethylsulfanylthiocarbonylsulfanyl)pentanoic acid (CEP) or 4-cyanopentanoic acid dithiobenzoate (CTP), resulting in polymers of broad molecular weight distributions (Mw/Mn > 1.20). As well, chain extension of a poly(methacryloyl sulfacetamide) (pSAC) macro-CTA at 70 °C was unsuccessful, indicating a loss of “living” chain ends during polymerization. However, by conducting the RAFT polymerization of MSAs at 30 °C with 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), polymers with narrow molecular weight distributions (Mw/Mn < 1.15) and improved chain end retention were obtained. Homopolymers of each MSA derivative were synthesized, and the influence of the sulfonamide R group on monomer pKa and pH-dependent polymer solubility was determined during these studies. The facility by which these controlled poly(MSAs) can be prepared via low-temperature RAFT without the need for functional group protection and the resulting pKa-dependent pH- and CO2-responsive properties point to significant potential in areas including drug and gene delivery and environmental remediation.
Publication Title
Macromolecules
Volume
48
Issue
16
First Page
5487
Last Page
5495
Recommended Citation
Abel, B. A.,
Sims, M. B.,
McCormick, C. L.
(2015). Tunable pH-and CO2-Responsive Sulfonamide-Containing Polymers by RAFT Polymerization. Macromolecules, 48(16), 5487-5495.
Available at: https://aquila.usm.edu/fac_pubs/15190
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