Al Nakeeb Noah, Nischang Ivo, Schmidt Bernhard V K J
Max-Planck Institute of Colloids and Interfaces, Department of Colloid Chemistry, Am Mühlenberg 1, 14476 Potsdam, Germany.
Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743 Jena, Germany.
Nanomaterials (Basel). 2019 Apr 26;9(5):662. doi: 10.3390/nano9050662.
The self-assembly of block copolymers in aqueous solution is an important field in modern polymer science that has been extended to double hydrophilic block copolymers (DHBC) in recent years. In here, a significant improvement of the self-assembly process of DHBC in aqueous solution by utilizing a linear-brush macromolecular architecture is presented. The improved self-assembly behavior of poly(-vinylpyrrolidone)--poly(oligo(ethylene glycol) methyl ether methacrylate) (PVP--P(OEGMA)) and its concentration dependency is investigated via dynamic light scattering (DLS) (apparent hydrodynamic radii ≈ 100-120 nm). Moreover, the DHBC assemblies can be non-covalently crosslinked with tannic acid via hydrogen bonding, which leads to the formation of small aggregates as well (apparent hydrodynamic radius ≈ 15 nm). Non-covalent crosslinking improves the self-assembly and stabilizes the aggregates upon dilution, reducing the concentration dependency of aggregate self-assembly. Additionally, the non-covalent aggregates can be disassembled in basic media. The presence of aggregates was studied via cryogenic scanning electron microscopy (cryo-SEM) and DLS before and after non-covalent crosslinking. Furthermore, analytical ultracentrifugation of the formed aggregate structures was performed, clearly showing the existence of polymer assemblies, particularly after non-covalent crosslinking. In summary, we report on the completely hydrophilic self-assembled structures in solution formed from fully biocompatible building entities in water.
嵌段共聚物在水溶液中的自组装是现代聚合物科学中的一个重要领域，近年来已扩展到双亲水嵌段共聚物（DHBC）。本文介绍了利用线性刷状大分子结构对DHBC在水溶液中的自组装过程进行的显著改进。通过动态光散射（DLS）（表观流体动力学半径≈100 - 120 nm）研究了聚（乙烯基吡咯烷酮）-聚（低聚乙二醇甲基醚甲基丙烯酸酯）（PVP - P（OEGMA））改进后的自组装行为及其浓度依赖性。此外，DHBC组装体可以通过氢键与单宁酸非共价交联，这也导致形成小聚集体（表观流体动力学半径≈15 nm）。非共价交联改善了自组装过程，并在稀释时稳定聚集体，降低了聚集体自组装的浓度依赖性。此外，非共价聚集体可以在碱性介质中解离。通过低温扫描电子显微镜（cryo - SEM）和DLS研究了非共价交联前后聚集体的存在情况。此外，对形成的聚集体结构进行了分析超速离心，清楚地表明了聚合物组装体的存在，特别是在非共价交联之后。总之，我们报道了由完全生物相容性构建实体在水中形成的溶液中完全亲水的自组装结构。
