Yang Jianping, Huang Bei, Lv Zhengxiang, Cao Zheng
Department of Orthopedics, Changzhou Hospital of Traditional Chinese Medicine 25 Heping North Road Changzhou 213000 Jiangsu P. R. China
Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, School of Materials Science and Engineering, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University Changzhou 213164 Jiangsu P. R. China
RSC Adv. 2023 Jan 24;13(6):3425-3437. doi: 10.1039/d2ra06678e.
Using -isopropyl acrylamide (NIPAM) as the main monomer, 1-vinyl imidazole (VIM) containing tertiary amine groups as the functional comonomer, and 1,5-dibromo pentane as the crosslinking agent, ionic P(NIPAM--VIM) microgels were prepared by a two-step method. The crosslinking agent was reacted with tertiary amino groups by the quaternary amination. The results of zeta potential and particle size analysis showed that P(NIPAM--VIM) microgels were positively charged and had a particle size of about 400 nm, and the microgels with 11 wt% VIM still showed temperature sensitivity with a volume phase transition temperature of approximately 37.5 °C. The effects of VIM content, ambient temperature, and pH on the adsorption properties of the microgels for phosphate anions were explored. The self-assembly of the positively charged P(NIPAM--VIM) microgels with polyelectrolytes and the adsorption behavior of the layers for phosphate anions were studied using a quartz crystal microbalance (QCM). It was found that at a phosphate concentration of 0.3 mg mL, VIM mass fraction of 11%, pH of 5, and temperature of 20 °C, the largest adsorption capacity of P(NIPAM--VIM) microgel on phosphate ions could reach 346.3 mg g. The frequency responses of the microgel-modified QCM sensor could reach 3.0, 18.8, and 25.9 Hz when exposed to 10, 10, and 10 M phosphate solutions. Therefore, the ionic (PNIPAM--VIM) microgels could be promising for fabricating anion-binding materials for separation and sensing applications.
以异丙基丙烯酰胺（NIPAM）为主要单体，含叔胺基团的1-乙烯基咪唑（VIM）为功能共聚单体，1,5-二溴戊烷为交联剂，采用两步法制备了离子型P（NIPAM-VIM）微凝胶。交联剂通过季铵化反应与叔氨基发生反应。zeta电位和粒径分析结果表明，P（NIPAM-VIM）微凝胶带正电，粒径约为400 nm，含11 wt% VIM的微凝胶仍表现出温度敏感性，体积相变温度约为37.5℃。研究了VIM含量、环境温度和pH值对微凝胶吸附磷酸根阴离子性能的影响。利用石英晶体微天平（QCM）研究了带正电的P（NIPAM-VIM）微凝胶与聚电解质的自组装以及层对磷酸根阴离子的吸附行为。结果发现，在磷酸根浓度为0.3 mg/mL、VIM质量分数为11%、pH值为5、温度为20℃时，P（NIPAM-VIM）微凝胶对磷酸根离子的最大吸附量可达346.3 mg/g。当暴露于10⁻¹⁰、10⁻⁹和10⁻⁸ M的磷酸盐溶液中时，微凝胶修饰的QCM传感器的频率响应分别可达3.0、18.8和
