Thermo- and pH-responsive copolymer poly(t-butyl acrylate)-b-poly{[2-(dimethylamino) ethyl methacrylate]-co-[poly(ethylene glycol) methyl ether methacrylate]}: Preparation, characterization, and their applications as organic dye adsorbents and drug delivery systems

Abstract

Temperature and pH double-response poly(t-butyl acrylate)-b-poly{[2-(dimethylamino) ethyl methacrylate]-co-[poly(ethylene glycol) methyl ether methacrylate]} (PtBA-b-P(DMAEMA-co-PEGMEMA)) were successfully prepared by RAFT polymerization and could be self-assembled into micelles. 1H NMR, UV-vis absorbance and DLS measurements were used to characterize their structures and self-assembly behaviors. At the same time, the adsorption of organic dyes and the control of drug release were also introduced. The results showed that the critical micelle concentration of PtBA-b-P(DMAEMA-co-PEGMEMA) was 2.55 mg/L. As the value of pH increased from 2 to 11, their particle size decreased from 178 nm to 130 nm. PtBA-b-P(DMAEMA-co-PEGMEMA) was also temperature responsive, with the hydrophobic block grows, the temperature of the particle mutation would increase. Therefore, PtBA-b-P (DMAEMA-co-PEGMEMA) could control the transfer and release of organic dyes such as methyl red and dithizone through their pH-sensitive properties, and the process had good reversibility. Meanwhile, PtBA-b-P(DMAEMA-co-PEGMEMA) micelles could also deliver some specific hydrophobic anticancer drug, such as camptothecin (CPT). In conclusion, the copolymers synthesized in this work have potential applications in the fields of environmental protection and drug delivery.