de Jongh Patrick A J M, Mortiboy Alice, Sulley Greg S, Bennett Mechelle R, Anastasaki Athina, Wilson Paul, Haddleton David M, Kempe Kristian
Department of Chemistry, University of Warwick, CV4 7AL, Coventry, United Kingdom.
ACS Macro Lett. 2016 Mar 15;5(3):321-325. doi: 10.1021/acsmacrolett.5b00904. Epub 2016 Feb 12.
We report the synthesis of dual-responsive -acylated poly(aminoester) (NPAE)-based comb polymers with varying molecular composition and monomer sequence via a combination of spontaneous zwitterionic copolymerization and redox-initiated reversible addition-fragmentation chain transfer (RRAFT) polymerization. NPAE macromonomers were synthesized from different nucleophilic (M), for example, 2-ethyl-2-oxazoline (EtOx) or 2-ethyl-2-oxazine (EtOz), and electrophilic monomers (M), for example, acrylic acid (AA) or 2-carboxyethyl acrylate (CEA), to tune the hydrophilicity and sequence of the systems. The latter was found to influence the thermal properties and stability of the respective comb polymers. Turbidity investigations in aqueous solution revealed a dual-responsive behavior of the comb polymers being responsive to both temperature and pH changes due to ω-carboxylic end groups of the NPAE-based macromonomers. Additional methylene groups in the NPAE backbone rendered the corresponding systems more hydrophobic and, hence, decreased the cloud point temperatures and, at the same time, increased the pH values (at constant temperature) at which the polymer phase separates from the aqueous solution.
我们报告了通过自发两性离子共聚和氧化还原引发的可逆加成-断裂链转移（RRAFT）聚合相结合的方法，合成了具有不同分子组成和单体序列的基于双响应ω-酰化聚（氨基酯）（NPAE）的梳状聚合物。NPAE大分子单体由不同的亲核单体（M），例如2-乙基-2-恶唑啉（EtOx）或2-乙基-2-恶嗪（EtOz），以及亲电单体（M），例如丙烯酸（AA）或丙烯酸2-羧乙酯（CEA）合成，以调节体系的亲水性和序列。发现后者会影响相应梳状聚合物的热性能和稳定性。水溶液中的浊度研究表明，由于基于NPAE的大分子单体的ω-羧酸端基，梳状聚合物具有对温度和pH变化均响应的双响应行为。NPAE主链中的额外亚甲基使相应体系更疏水，因此降低了浊点温度，同时提高了聚合物从水溶液中相分离时的pH值（在恒定温度下）。
