Ye Liandong, Liu Min, Wang Xiao, Yu Zhihong, Huang Zhihao, Zhou Nianchen, Zhang Zhengbiao, Zhu Xiulin
Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University Suzhou 215123 China
RSC Adv. 2023 Aug 11;13(35):24181-24190. doi: 10.1039/d3ra04205g.
Sequences can have a dramatic impact on the unique properties and self-assembly in natural macromolecules, which has received increasing interest. Herein, we report a series of discrete amphiphilic co-oligomers with the same composition but different building blocks in a semirigid backbone. These sequence-defined oligomers possess two primary amine groups on the side chain of the azobenzene building block, and hence, they become amphipathic due to quaternization of the amine groups when protonated in acidic aqueous solution. These oligomer isomers assembled into different nanoparticles, including nanofibers, hollow vesicles and spherical micellar complexes, in a THF/water/HCl mixture under the same conditions. UV-vis absorption spectra, differential scanning calorimetry (DSC) and X-ray scattering (XRD) experiments combined with theoretical calculations reveal that the sequence-controlled co-oligomers induce different molecular packing conformations and arrangement modes of building blocks in self-assembly. Furthermore, these self-assembled nanoparticles demonstrate photoresponsive morphological transformation and fluorescence emission under UV light irradiation due to -to- photoisomerization of azobenzene. This work demonstrates that customizing functional nanoparticles can be achieved by controlling the sequence structure in synthetic co-oligomers.
序列对天然大分子的独特性质和自组装有着显著影响，这一点已引起越来越多的关注。在此，我们报道了一系列离散的两亲性共低聚物，它们具有相同的组成，但在半刚性主链中有不同的结构单元。这些序列定义的低聚物在偶氮苯结构单元的侧链上具有两个伯胺基团，因此，当在酸性水溶液中质子化时，由于胺基团的季铵化，它们变得具有两亲性。在相同条件下，这些低聚物异构体在四氢呋喃/水/盐酸混合物中组装成不同的纳米颗粒，包括纳米纤维、空心囊泡和球形胶束复合物。紫外可见吸收光谱、差示扫描量热法（DSC）和X射线散射（XRD）实验结合理论计算表明，序列控制的共低聚物在自组装中诱导了不同的分子堆积构象和结构单元排列模式。此外，由于偶氮苯的 - 光异构化，这些自组装纳米颗粒在紫外光照射下表现出光响应形态转变和荧光发射。这项工作表明，通过控制合成共低聚物中的序列结构可以实现定制功能性纳米颗粒。
