Simonova Maria, Kamorin Denis, Filippov Alexander, Kazantsev Oleg
Institute of Macromolecular Compounds of the Russian Academy of Sciences, Bolshoy Prospekt 31, 199004 Saint Petersburg, Russia.
Research Laboratory "New Polymeric Materials", Nizhny Novgorod State Technical University n.a. R.E. Alekseev, 24 Minin Street, 603950 Nizhny Novgorod, Russia.
Polymers (Basel). 2023 Mar 25;15(7):1641. doi: 10.3390/polym15071641.
The thermo- and pH-responsive polymer brushes based on methoxy[oligo(propyleneglycol)-block-oligo(ethyleneglycol)]methacrylate with different concentrations of N-[3-(dimethylamino)propyl]methacrylamide (from 0% to 20%) were synthesized via RAFT polymerization. The "grafting-through" approach was used to prepare the low-molar-mass dispersion samples (/ ≈ 1.3). Molar masses and hydrodynamic characteristics were obtained using static and dynamic light scattering and viscometry. The solvents used were acetonitrile, DMFA, and water. The molar masses of the prepared samples ranged from 40,000 to 60,000 g·mol. The macromolecules of these polymer brushes were modeled using a prolate revolution ellipsoid or a cylinder with spherical ends. In water, micelle-like aggregates were formed. Critical micelle concentrations decreased with the content of N-[3-(dimethylamino)propyl]methacrylamide. Molecular brushes demonstrated thermo- and pH-responsiveness in water-salt solutions. It was shown that at a given molecular mass and at close pH values, the increase in the number of N-[3-(dimethylamino)propyl]methacrylamide units led to an increase in phase separation temperatures.
通过可逆加成-断裂链转移（RAFT）聚合反应合成了基于甲氧基[聚丙二醇-嵌段-聚乙二醇]甲基丙烯酸酯且含有不同浓度N-[3-(二甲氨基)丙基]甲基丙烯酰胺（从0%至20%）的热响应和pH响应聚合物刷。采用“接枝-通过”方法制备了低摩尔质量分散样品（/≈1.3）。使用静态和动态光散射以及粘度测定法获得了摩尔质量和流体动力学特性。所使用的溶剂为乙腈、N,N-二甲基甲酰胺和水。制备样品的摩尔质量范围为40,000至60,000 g·mol。这些聚合物刷的大分子采用长轴旋转椭球体或两端为球形的圆柱体进行建模。在水中形成了胶束状聚集体。临界胶束浓度随N-[3-(二甲氨基)丙基]甲基丙烯酰胺的含量降低。分子刷在水盐溶液中表现出热响应和pH响应。结果表明，在给定分子量和相近pH值下，N-[3-(二甲氨基)丙基]甲基丙烯酰胺单元数量的增加导致相分离温度升高。
