P(NIPAm-AABC-NMA)温敏微凝胶自组装膜及其重金属离子选择性

P(NIPAm-AABC-NMA) thermo-sensitive microgels self-assembled film and its selective response to heavy metal ions

摘要:

以N-异丙基丙烯酰胺（NIPAm）为单体，丙烯酸（AA）和N-羟甲基丙烯酰胺（NMA）为功能单体，通过自由基乳液聚合制备P(NIPAm-AA-NMA)微凝胶，利用N-(3-二甲基氨基丙基)-N'-乙基-碳二亚胺盐酸盐（EDC）的耦合作用，实现4'-氨基苯并-18-冠醚-6(ABC)对微凝胶的修饰，合成P（NIPAm-AABC-NMA）微凝胶；进一步，通过溶剂挥发制备微凝胶自组装膜。采用FTIR、SEM和DLS表征微凝胶及其自组装膜的微观结构；采用UV-Vis研究自组装膜的温敏性及其对金属离子的选择响应性能。结果表明，ABC修饰前、后微凝胶粒径分别为240和300nm左右，随环境温度或离子浓度变化，自组装膜中微凝胶粒径随之变化，自组装膜对入射光的衍射发生显著变化，而呈现不同的结构色。特别是，当Pb2+浓度在0~120μmol/L之间变化时，自组装膜衍射峰红移60nm左右。

Abstract:

In this paper, P(NIPAm-AA-NMA) microgels were synthesized with N-isopropylacrylamide (NIPAm), acrylic acid (AA) and N-hydroxymethylacrylamide (NMA) by free radical emulsion polymerization. Then 4'-aminobenzo-18-crown-6 (ABC) decorated P(NIPAm-AA-NMA) microgels〔P(NIPAm-AABC-NMA)〕were prepared by using N-(3-dimethylaminopropyl)-N'-ethyl-carbodiimide hydrochloride (EDC) as condensation agent. Finally, the P(NIPAm-AABC-NMA) microgels self-assembled films were fabricated by the solvent evaporation method. The microstructure of microgels and self-assembled films were characterized by FTIR, SEM and DLS. Moreover, the temperature-sensitive properties of self-assembled films and their selective response to metal ions were investigated by UV-Vis. The results indicated that the particle size of the microgels before and after decoration by ABC was about 240 nm and 300 nm, respectively. With variation of environmental temperature or concentration of heavy metal ions, the particle size of the microgels in the self-assembled film changed accordingly, the incident light could be diffracted by the self-assembled film, and different structural colors of the film could be observed. In particular, when the Pb2+ concentration changes between 0 and 120 μmol/L, the red-shift of the self-assembled film diffraction peak was about 60 nm.