Thin Film Assemblies of Molecularly-Linked Metal Nanoparticles and Multifunctional Properties

Abstract

The use of metal nanoparticles as building blocks toward thin film assembly creates intriguing opportunities for exploring multifunctional properties. Such an exploration requires the ability to engineer the size, shape, composition, and especially interparticle properties in nanoparticle assemblies for harnessing the collective properties of the nanoscale building blocks. This article highlights some of the important findings of our investigations of thin film assemblies of molecularly linked nanoparticles for exploiting their multifunctional and collective properties in molecular recognition and chemical sensing. The thermally activated processing approach presents a viable pathway for nanoengineering metal, alloy, and core-shell nanoparticles as building blocks. The molecular mediator-templating approach offers an effective strategy to thin film assemblies of the nanoscale building blocks that impart multifunctional properties. In such thin film assemblies, the interparticle interactions and structures dictate the correlation between the nanostructural parameters and the optical and electrical properties. By highlighting selected examples involving ligand-framework binding of ionic species at the film/liquid interface and electrical responses to molecular sorption at the film/gas interface, the multifunctional properties of the thin film assemblies are further discussed in terms of interparticle covalent, hydrogen bonding, ionic, or van der Waals interactions in a framework-type architecture for the creation of molecular recognition and chemical sensing sites that can be tuned chemically or electrochemically. Implications of these insights to expanding the exploration of nanoparticle thin film assemblies for a wide range of technological applications are also discussed.

Nanostructured copper oxides and phosphates from a new solid-state route

“…The exploration of nanostructured copper-based materials as building blocks towards multifunctional materials with technological applications requires, among others, their incorporation in a solid-state phase, usually as thin films [10]. Thus the preparation methods for nanostructured materials in their solid-state phase are of great importance.…”

“…Thus the preparation methods for nanostructured materials in their solid-state phase are of great importance. Specifically for copper oxides, solid-state preparation methods have been reported [6,7,[10][11][12][13][14][15][16]. Xu et al [7] prepared CuO nanocrystals by a one-step solid-state reaction of CuCl 2 ⋅2H 2 O and NaOH, while Kawahashi and Shiho [6] obtained hollow spheres by calcination of a polymer-coated Cu(NO 3 ) 2 salt.…”

“…Xu et al [7] prepared CuO nanocrystals by a one-step solid-state reaction of CuCl 2 ⋅2H 2 O and NaOH, while Kawahashi and Shiho [6] obtained hollow spheres by calcination of a polymer-coated Cu(NO 3 ) 2 salt. A different approach involves the oxidation of solid Cu under air at 400 °C to give CuO nanorods [10]. Similarly large-scale synthesis of CuO nanowires has been reported by thermal evaporation of a copper foil under oxygen flow [11].…”

Functionalized gold nanoparticles for the binding, stabilization, and delivery of therapeutic DNA, RNA, and other biological macromolecules

“…Controlling interparticle proximity by changing the length of DNA linkers allows for elaborate monolayer construction such as sheets with evenly spaced wells. 25 These monolayers can also be stacked and arranged in alternating molecular patterns through layerby-layer deposition. [26][27][28] Another means that may be amenable for attaching macromolecular DNA or RNA is by coating the gold surface with alternating layers of cationic and anionic polyelectrolytes.…”

Transdermal treatment of the surgical and burned wound skin via phytochemical-capped gold nanoparticles

“…[7][8][9] It is often reported that the chemical properties of the stabilizers can be enhanced through interaction with the core metallic materials during optical and electrical analysis. [10,11] Since the stabilizers are usually bio-hazardous chemicals that are used to confine core materials' size and shape restriction, they would provoke unexpected side effects. Thus, a great effort has been made to synthesize biologically inert/compatible NPs.…”