2D Monolayer Films Of Gold Nanoparticles: Fabrication Strategies,Polymer Functionalization And Applications

Assembly gold nanoparticles(Au NPs)with a certain morphology and particle size into macroscopic two-dimensional monolayer has attracted extensive attention for a wide variety of applications ranging from sensing,detection,intelligent bionics,flexible devices,etc.However,it is still difficult to construct Au NPs monolayer with tunable particle arrangement and spacing in present investigations.In order to realize the optimization of Au NPs monolayer and expand its application,this paper mainly focus on the following work through the functionalization of Au NPs monolayer:(1)Constructing macroscopic orientational and freestanding gold nanorods(Au NRs)monolayer films with excellent photothermal anti-counterfeiting performance.Although the alignment of Au NRs can be achieved by the local affinity between the solid substrate and Au NRs,the presence of substrates greatly limits the application of the Au NRs monolayer films.In order to overcome the limitation of the solid substrate in the assembly process,the macroscopic Au NRs monolayer was assembled at the water-oil interface by the precise asymmetric modification of Au NRs,and the controllable orientation assembly of Au NRs could be realized by controlling the ratio and amount of molecular modified on the surface of Au NRs.Furthermore,the optimized Au NRs assemblies showed excellent photo thermal conversion ability,and achieved higher temperature conversion at lower energy density.Thus,the optimized Au NRs orientational assemblies showed great application potential in photothermal anti-counterfeiting.(2)Strong hydrophobic force induced fast construction of macroscopic 2D Au NPs monolayer films.The traditional water-oil interfacial assembly often limited due to the disadvantages including tedious film forming approach,susceptible to external interference,uncontrollable assembly morphology and particle spacing,easy to break,and low availability of Au NPs.Here,the hydrophobic molecule with extremely low surface energy was induced to form Au NPs monolayer.The driving force of Au NPs film formation was extremely enhanced from the perspective of thermodynamics and dynamics.In addition,this approach was with extremely fast film-forming speed,high utilization of Au NPs,large area,and the formation of a uniform monolayer structure with densely arranged particles.Moreover,due to the ultra-low surface energy of perfluorinated molecules,the 2D Au NPs monolayer films have some special properties,including easy transfer and rendition,and this approach can be widely applied to other morphologies(precious metal or non precious metals).More importantly,this Au NRs monolayer film possesses strong self-healing capability,which can be applied to adsorb other substances,such as iron ions(Fe³⁺).The Fe³⁺with high concentration can be adsorbed under a small amount of Au NPs.Moreover,the 2D Au NPs monolayer film can bear multiple self-healing adsorption cycles and maintain good membrane stability.(3)Constructing 2D Au NPs superlattices for self-cleaning and sensitive detection.The preparation of 2D Au NPs superlattices has always been a research hotspot.The traditional Au NPs superlattices not only have harsh film forming conditions,but also possess a strong dependence on superlattice substrates.More importantly,the properties of the Au NPs superlattices cannot be utilized.Au NPs superlattice self-assembly is induced by perfluorinated molecules with ultra-low surface energy while giving the Au NPs superlattices some special properties,and further used in self-cleaning SERS detection.