摘要
采用对N-异丙基丙烯酰胺-丙烯酸共聚微凝胶进行改性的方法合成了含苯并18-冠-6功能基团的PNIPAM微凝胶.红外和核磁光谱等手段证明苯并18-冠-6基团被引入到微凝胶中.改性后的微凝胶仍具有很好的温敏性,但是相转变温度由改性前的30℃提高到42℃,并且溶胀度也大大增加.在不控制离子强度的条件下微凝胶的粒径随Na+浓度增加而减小,但是随Pb2+浓度增加微凝胶粒径先减后增.在控制离子强度不变的条件下Na+浓度对微凝胶的粒径影响很小,但是随Pb2+浓度增加微凝胶粒径明显增大,显示较强的铅离子敏感性。
Poly（N-isopropylacrylamide） microgel with functional benzo-18-crown-6 group was synthesized by modifying a parent poly（N-isopropylacrylamide-co-acrylic acid） microgel with 4＇-aminobenzo18-crown-6 under EDC catalysis.The introduction of the functional groups was confirmed by IR and NMR.The resultant microgel is still thermosensitive,but the volume phase transition temperature shifts from 30℃ to 42℃.The swelling degree of the microgels increases too,indicating the 4＇-acrylamidobenzo-18-crown-6 monomer acts as an hydrophilic one.The effects of Na ＋ and Pb2 ＋ on the microgel size were studied by dynamic light scattering.When ionic strength is not controlled,the microgel size decreases with increasing [NaCl],but first decreases followed by increasing with increasing [Pb（NO3）2].When ionic strength is kept constant,increasing [Na^ ＋ ] has little effect on microgel size.In contrast,microgel size expands significantly with increasing [Pb^2 ＋ ].In this case,the effect of ionic strength was avoided.Because of its high affinity to 18-crown-6,the binding of Pb^2 ＋ with crown ether further increases its hydrophilicity,so the microgels swell to a larger extent.However the binding constant between Na ^＋ and 18-crown-6 is small,therefore it induces little swelling of the microgel particles.The light scattering results also show a narrow size distribution of the microgels.The monodisperse,lead-sensitive microgel may find application for the fabrication of new lead sensors.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2010年第6期793-796,共4页
Acta Polymerica Sinica
基金
科技部国际科技合作项目(基金号2007DFA50760)
国家自然科学基金(基金号20974050)
教育部博士点基金新教师项目(基金号20070055079)资助项目
关键词
微凝胶
离子敏感
温度敏感
铅
Microgels
Ion sensitive
Thermosensitive
Lead
