双重响应性纳米凝胶的制备及其结构色调控

Preparation and tunable structural color of dual-responsive nanogels

通过酰氯化反应成功合成了一种新型的弱酸性单体L-N-丙烯酰基苯丙氨酸(APhe),采用乳液沉淀共聚的方法将此单体与温敏性单体N-异丙基丙烯酰胺(NIPA)进行共聚,合成了共聚纳米凝胶P(NIPA-co-APhe)。利用红外光谱仪、TEM对制备样品的结构、形貌进行了测试表征,表征结果显示纳米凝胶呈球状并具有良好的单分散性,使用粒度分析仪对纳米凝胶进行分析,发现纳米凝胶具有良好的温敏性及pH敏感性。使用光纤光谱仪对其结构色进行了表征,发现可以通过调节单体配比、pH值来调节纳米凝胶的结构色。进一步发现,新型P(NIPA-co-APhe)纳米凝胶发生相变后,依然能保持亮丽的结构色。

A weakly acidic monomer L-N-acryloyl phenylalanine(APhe)was synthesized.Poly(NIPA-co-APhe)copolymer nanogels were synthesized by emulsion precipitation copolymerization of the monomer Aphe with the thermosensitive monomer N-isopropylacrylamide(NIPA).The structure and morphology of the nanogels prepared were characterized by IR and TEM,respectively.The results show that the particles of nanogels are spherical and monodispersed.The nanogels were also analyzed by particle size analyzer.It is found that the nanogels have good temperature/pH sensitivities.That is,the particle size is gradually decreased with the increase of temperature,and the particle size is first increased and then decreased with the increase of pH.The structural color was characterized by optical fiber spectrometer.It is found that the structural color of the nanogels can be adjusted by varying the monomer ratio and pH value.That is,the particle size is gradually increased with the increase of molar fraction of monomer APhe,and the color is gradually changed from green to blue as the compression degree of the particles is increased.Furthermore,it is important to observe that the Poly(NIPA-co-APhe)nanogels even keep the structural color in the case of undergoing a temperature-induced phase transition.