Tunable pH- and CO2-Responsive Sulfonamide-Containing Polymers by RAFT Polymerization

详细信息    查看全文

• 作者：Brooks A. Abel ; Michael B. Sims ; Charles L. McCormick
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：August 25, 2015
• 年：2015
• 卷：48
• 期：16
• 页码：5487-5495
• 全文大小：450K
• ISSN：1520-5835

文摘

The controlled RAFT polymerization of a library of pH- and CO<sub>2sub>-responsive methacryloyl sulfonamides (MSAs) that possess pK<sub>asub> values in the biologically relevant regime (pH = 4.5鈥?.4) is reported. Initial polymerizations were conducted at 70 掳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 (M<sub>wsub>/M<sub>nsub> > 1.20). As well, chain extension of a poly(methacryloyl sulfacetamide) (pSAC) macro-CTA at 70 掳C was unsuccessful, indicating a loss of 鈥渓iving鈥?chain ends during polymerization. However, by conducting the RAFT polymerization of MSAs at 30 掳C with 2,2鈥?azobis(4-methoxy-2,4-dimethylvaleronitrile), polymers with narrow molecular weight distributions (M<sub>wsub>/M<sub>nsub> < 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 pK<sub>asub> 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 pK<sub>asub>-dependent pH- and CO<sub>2sub>-responsive properties point to significant potential in areas including drug and gene delivery and environmental remediation.