多重敏感性双亲共聚物P(DM-co-AA-co-CA)的自组装及性能

Self-assembly and Properties of Multi-sensitive Amphiphilic P(DM-co-AA-co-CA) Copolymer

以甲基丙烯酸二甲胺乙酯(DM)、丙烯酸(AA)和香豆素丙烯酸酯化物(CA)为共聚单体,通过普通自由基溶液聚合合成了多重敏感性双亲共聚物P(DM-co-AA-co-CA),用傅里叶变换红外光谱(FTIR)、核磁共振谱(1H NMR)、凝胶渗透色谱(GPC)和差示扫描量热仪(DSC)对聚合物结构进行表征.在选择性溶剂四氢呋喃/水中对P(DM-co-AA-co-CA)进行自组装,结果表明,调节组装环境的pH值可得到荷正电或负电的两性胶束粒子.用紫外-可见光分光光度计、Zeta电位测定仪、动态激光散射仪和透射电子显微镜研究了多重敏感性双亲共聚物溶液自组装及组装体的性能,结果表明,调节pH值可以有效控制胶束的粒径大小及其低临界溶液温度(LCST),在pH=8.54时胶束溶液的紫外吸收和荧光发射强度达到最大值.

Coumarin-containing acrylic acid monomer（CA） was designed and synthesized,which could be used together with dimethylaminoethyl methacrylate（DM） and acrylic acid（AA） to synthesize the multi-sensitive amphiphilic copolymer P（DM-co-AA-co-CA） via free radical copolymerization.Its structure was characterized by Fourier transform infrared spectroscopic（FTIR）,magnetic resonance spectrometer（1H NMR）,gel permeation chromatography（GPC） and differential scanning calorimeter（DSC）.The copolymer could self-assemble into steady spherical micelles in the selective solvent THF/water with suitable initial copolymer concentration and water content.The self-assembly process and characteristic of P（DM-co-AA-co-CA） micelles were studied by UV spectrophotometer,zeta potential,dynamiclaser light scattering（DLS） and transmission electron microscope（TEM）.The results show that in the range of pH=2.13-8.54,the UV absorbance of micellar solutions increase with increasing of pH value,and in the range of pH=8.54-12.46,both of them decrease with increasing of pH value.Depending on the solution pH,these micelles can exist in two different micellar charge states and an isoelectric point at around pH=9.70,around which the diameter of micelle particles became the smallest,and then it increased either with the pH value increasing or decreasing.In basic solution,LCST of micelles decreased with increasing of pH value.