Synthesis and micellar characterization of an amphiphilic diblock copolyphosphazene
Synthesis and micellar characterization of an amphiphilic diblock copolyphosphazene
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DOI：
10.1021/ma992036l
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发表时间：
2001-01-16
期刊：
影响因子：
5.5
通讯作者：
Allcock, HR
中科院分区：
文献类型：
--
作者：
Chang, Y;Lee, SC;Allcock, HR
以N=P（OCH（2）CH 2 OCH 2CH 2 OCH 3）（2）]（n）（MEEP）和[N=PPh（OCH（2）CH 2 OCH（2）CH（2）OCH（3））]（m）（Ph/MEEP）为亲水嵌段，通过正膦胺的可控阳离子嵌段共聚，合成了两亲性聚磷腈嵌段共聚物（MEEP-Ph/MEEP）。通过GPC估计嵌段共聚物的分子量为3300。MEEP嵌段中的重复单元与Ph/MEEP嵌段中的重复单元的摩尔组成比为0.5。用荧光光谱、动态光散射和透射电镜对MEEP-Ph/MEEP在水相中的胶束进行了表征。嵌段共聚物形成的胶束的临界胶束浓度（cmc）为80 mg/L。动态光散射法测得胶束的流体动力学半径（R-h）在25 ℃时为120 nm，分布较窄。TEM图像显示胶束具有球形形状。在高于57 ℃的温度下，嵌段共聚物的胶束溶液中出现了胶束间聚集.芘在嵌段共聚物胶束溶液中的分配平衡常数K-v为7.0 × 10 ~（3）。1，6-二苯基-1，3，5-己三烯（DPH）的稳态荧光各向异性值（r）为0.237。嵌段共聚物溶液中DPH的荧光寿命值表明胶束的核心区域由两个疏水性不同的区域组成。
An amphiphilic polyphosphazene diblock copolymer (MEEP-Ph/MEEP) based on [N=P(OCH2CH2OCH2CH2OCH3)(2)](n)(MEEP) as a hydrophilic block and [N=PPh(OCH(2)CH2OCH(2)CH(2)OCH(3))](m)(Ph/MEEP) as a hydrophobic block was synthesized via the controlled cationic block copolymerization of phosphoranimine. The molecular weight of the block copolymer was estimated by GPC to be 3300. The molar composition ratio of repeating unit in the MEEP block to those in the Ph/MEEP block was 0.5. The micellar characterization of MEEP-Ph/MEEP in an aqueous phase was carried out by using fluorescence techniques, dynamic light scattering, and TEM. The block copolymer formed micelles with a critical micelle concentration (cmc) of 80 mg/L. The hydrodynamic radius (R-h) of micelles, measured by dynamic light scattering, was 120 nm at 25 degreesC with a narrow distribution. The TEM image showed micelles with a spherical shape. Intermicellar aggregation was induced in the micellar solution of the block copolymer above 57 degreesC. The partition equilibrium constant, K-v, of pyrene in the micellar solution of the block copolymer was 7.0 x 10(3). The steady-state fluorescence anisotropy value (r) of 1,6-diphenyl-1,3,5-hexatriene (DPH) was 0.237. The fluorescence lifetime value for DPH in the block copolymer solution showed that the core region of the micelles consisted of two regions with different hydrophobicities.