Functionalization of MoS2 and WS2 sulfide nanotubes: From controlled synthesis to organized assembly and function

本项目研究硫族化合物纳米管与有机和聚合物配体的功能化，以便：(1)调整硫族化合物纳米管在各种极性或非极性溶剂中的溶解度和/或将其整合到无机/聚合物杂化结构中；(2)将光激发或氧化配体（例如用于光捕获的金属卟啉）结合到管的侧壁上；(3)将金属（Au, Ag），半导体（ZnS, ZnS）等纳米颗粒附着在管的侧壁上。（iv）在氧化或陶瓷表面上用MoS2纳米管制造薄膜，用MoS2和/或WS2纳米管和聚电解质生产一层一层组装的复合材料，(v)在表面上附着配体，以建立有组织的硫系纳米管组装体。本文的研究重点是二硫化钼和WS2纳米管，这两种纳米管的数量和质量都是足够的。功能化策略是基于三脚架或四脚架配体，这些配体通过过渡金属（Ni2+或Co2+）结合到硫族化物管的外表层，过渡金属（Ni2+或Co2+）作为粘合剂连接配体。多重配体携带用于连接其他功能分子或纳米颗粒的连接基团和用于调节纳米管与所连接的颗粒或分子之间的分离的间隔基团。多pod配体可以作为侧基连接到嵌段共聚物的主链上，其中第二侧基携带功能配体，作为金属或半导体颗粒的锚基团。聚合物配体方法的优点是纳米管/配体复合物不依赖于单键的稳定性，而是依赖于多功能对接。用硝基三乙酸（NTA）在富勒烯型MoSz纳米颗粒上的实验证明了该方法的有效性。本研究的成功将为设计硫系纳米粒子的化学改性提供一个通用的方法，硫系纳米粒子的润滑和吸收（MoS2, WSn）和电子性能（NbS2, NbSe2）具有特别的兴趣。

ObjectivesThis project deals with the functionalization of chalcogenide nanotubes with organic and polymer ligands in order to(i) tailor the solubilities of chalcogenide nanotubes in various polar or unpolar solvents and/or to integrate them into inorganic/polymer hybrid structures,(ii) to bind photoexcitable or redoxactive ligands (e.g. metalloporphyrins for light harvesting) to the sidewalls of the tubes,(in) to attach nanoparticles such as metal (Au, Ag), semiconductor (ZnS, CdSe) particles to the sidewall of the tubes,(iv) to fabricate thin films from MoSa nanotubes on oxidic or ceramic surfaces and to produce layer-by-layer assembled composites from MoS2 and/or WS2 nanotubes and poiyelectrolytes,(v) attach ligands to the surface in order to build up organized assemblies of chalcogenide nanotubes.The proposed research will focus on MoS2 and WS2 nanotubes, which are available in sufficient amounts and quality.Methods and plan of operationThe functionalization strategy is based on tripod or tetrapod ligands which are bonded to the outer surface layer of the chalcogenide tube by transition metals (Ni2+ or Co2+) which act as a glue for the attachment of the ligand. The multiped ligand carries a linker group for the attachment of other functional molecules or nanoparticles and a spacer group for adjusting the separation between the nanotube and the particles or molecules attached. The multipod ligand can be attached as a sidegroup to the backbone of a block copolymer, where the second side group carries the functional ligands are acts as an anchor group for metal or semiconductor particles. The advantage of the polymer ligand approach is that the nanotube/ligand complex do not rely on the stability of a single bond but rather on multifunctional docking. The validity of this approach has been demonstrated with nitrilotriacetic acid (NTA) on fullerene-type MoSz nanoparticles.Significance of the proposed researchSuccessful performance of this research will provide a general methodology for a designed chemical modification of chalcogenide nanoparticles, which are of special interest for their lubricating and s hock-absorbing (MoS2, WSn) and electronic properties (NbS2, NbSe2).