Department of Chemical Engineering, Laboratory for Advanced Materials, Tsinghua University, Beijing, 100084, PR China.
Macromol Rapid Commun. 2011 Jul 1;32(13):977-82. doi: 10.1002/marc.201100142. Epub 2011 May 13.
In this work, an amphiphilic diblock copolymer (PEG(43)-b-PSDTE(29)) bearing photochromic dithienylethene (DTE) pendants is synthesized by reversible addition fragmentation chain transfer radical polymerization. The diblock copolymer was characterized by spectroscopic methods and gel permeation chromatography. The analyses proved the well-defined structure and narrow molecular weight distribution of the diblock copolymer. The DTE pendants could undergo reversible photoisomerization between their open and closed forms in solution when irradiated with UV and visible light as indicated by (1)H NMR and UV-vis spectroscopy. Hollow vesicle-like structures were formed by gradually adding deionized water to the colorless PEG(43)-b-PSDTE(29open) (DTE in open form) tetrahydrofuran solution. Under the same conditions, the aggregates formed in the blue PEG(43)-b-PSDTE(29close) (DTE in closed form) solution were colloidal spheres with solid interiors. The isomerization of DTE pendants could cause the deformation of the vesicle-like structures. The above results demonstrate a kind of novel photo-modulated self-assembly behavior of the amphiphilic diblock copolymer, which could be used for drug-delivery and other applications.
在这项工作中，通过可逆加成-断裂链转移自由基聚合合成了一种具有光致变色二噻吩乙烯（DTE）侧基的两亲性嵌段共聚物（PEG(43)-b-PSDTE(29)）。通过光谱方法和凝胶渗透色谱对嵌段共聚物进行了表征。分析证明了嵌段共聚物具有明确的结构和较窄的分子量分布。DTE 侧基在溶液中可以通过紫外光和可见光照射在其开环和闭环形式之间进行可逆光异构化，这一点通过（1）H NMR 和紫外-可见光谱得到了证明。当逐渐向无色的 PEG(43)-b-PSDTE(29open)（DTE 处于开环形式）四氢呋喃溶液中加入去离子水时，会形成空心囊泡状结构。在相同条件下，在蓝色的 PEG(43)-b-PSDTE(29close)（DTE 处于闭环形式）溶液中形成的聚集体是具有实心内部的胶体球。DTE 侧基的异构化会导致囊泡状结构的变形。上述结果表明了一种新型的两亲性嵌段共聚物的光调控自组装行为，可用于药物传递等应用。
