Han Xuwen, Tang Feng, Jin Zhaoxia
Department of Chemistry, Renmin University of China Beijing 100872 People's Republic of China
RSC Adv. 2018 May 18;8(33):18347-18354. doi: 10.1039/c8ra02930j. eCollection 2018 May 17.
Polydopamine is widely used in surface modification, nanofiltration, photonic devices and drug delivery. The formation mechanism and properties of polydopamine are modified by the experimental conditions. Herein we demonstrated a comparison study of free-standing polydopamine films generated at the air-solution interface and their corresponding nanoparticles in solutions, in the presence of various metallic cations, Na, Ca, Mg and Co. Adding metallic ions influenced the intermediates in dopamine polymerization, and in turn the morphology and properties of the produced free-standing polydopamine films. Moreover, we observed that the polymerization process accompanying the stratification determines the formation of free-standing films at the air-solution interface: the fast polymerization of dopamine in a Co environment leads to a rugged film surface and porous film body, whereas the comparatively slow polymerization of dopamine under conditions of other metallic ions results in a smooth and solid film. In addition, the water contact angles of the upper and lower surface of the polydopamine films were different. This investigation enriches our knowledge of dopamine polymerization in different environments, which is particularly useful for further application of free-standing polydopamine films.
聚多巴胺广泛应用于表面改性、纳滤、光子器件及药物递送领域。聚多巴胺的形成机制和性质会因实验条件而改变。在此，我们展示了一项对比研究，即在各种金属阳离子（Na、Ca、Mg和Co）存在的情况下，在气-液界面生成的独立聚多巴胺膜及其在溶液中的相应纳米颗粒。添加金属离子会影响多巴胺聚合过程中的中间体，进而影响所制备的独立聚多巴胺膜的形态和性质。此外，我们观察到伴随着分层的聚合过程决定了气-液界面处独立膜的形成：多巴胺在Co环境中的快速聚合导致膜表面粗糙且膜体多孔，而在其他金属离子条件下多巴胺相对缓慢的聚合则产生光滑且致密的膜。此外，聚多巴胺膜上下表面的水接触角不同。这项研究丰富了我们对多巴胺在不同环境中聚合的认识，这对于独立聚多巴胺膜的进一步应用尤为有用。
