Kaulen C, Simon U
JARA - FIT, RWTH Aachen University 52074 Aachen Germany
Institute of Inorganic Chemistry, RWTH Aachen University 52074 Aachen Germany.
RSC Adv. 2018 Jan 5;8(3):1717-1724. doi: 10.1039/c7ra10374c. eCollection 2018 Jan 2.
Since the pioneering work of F. Hofmeister, , 1888, , 247, ion specific effects have been steadily reported in the context of colloidal or protein stabilisation in electrolyte solutions. Although the observed effects are omnipresent in chemistry and biology, their origin is still under ferocious discussion. Here, we report on ion specific effects affecting the self-assembly of amine and carboxylic acid functionalised gold nanoparticles on metal surfaces as well as in electrolyte solution as a function of the monovalent cations Li, Na, K and Cs. Mercaptooctanoic acid and 1,8-amine-octanethiol functionalised gold nanoparticles were adsorbed on structured AuPd/Pt substrates under addition of the respective chloride salts. Furthermore, the influence of the same salts on the salt induced aggregation of these AuNP was investigated. Our results demonstrate that the assembly processes on the metal surface as well as in electrolyte solution are influenced by the addition of different cations. We attribute the observed effects to ion pairing of the functional end groups with the added cations. With these findings we introduce a new parameter to control the self-assembly of 2D AuNP arrays on solid supports or of 3D AuNP networks in solution, which could be of relevance for the fabrication of new tailor-made functional materials or for biomedical applications.
自1888年F.霍夫迈斯特的开创性工作以来（文献247），在电解质溶液中胶体或蛋白质稳定化的背景下，离子特异性效应一直不断被报道。尽管观察到的效应在化学和生物学中普遍存在，但其起源仍在激烈讨论中。在此，我们报道了作为单价阳离子Li、Na、K和Cs的函数，离子特异性效应影响胺和羧酸官能化金纳米颗粒在金属表面以及电解质溶液中的自组装。在添加相应氯化物盐的情况下，巯基辛酸和1,8 - 氨基辛烷硫醇官能化的金纳米颗粒吸附在结构化的AuPd/Pt基底上。此外，研究了相同盐对这些金纳米颗粒盐诱导聚集的影响。我们的结果表明，在金属表面以及电解质溶液中的组装过程受到不同阳离子添加的影响。我们将观察到的效应归因于官能端基与添加阳离子的离子配对。通过这些发现，我们引入了一个新参数来控制二维金纳米颗粒阵列在固体支持物上或溶液中三维金纳米颗粒网络的自组装，这对于新型定制功能材料的制造或生物医学应用可能具有相关性。
