Graphene (Coatings and Sensors)
Introduction
Nanoparticle deposition refers to the process of attaching nanoparticles to solid surfaces called substrates to create nanoparticle coatings. Coatings can have a single-layer or multi-layer layer and an organized or disorganized structure depending on the coating method used. Nanoparticles are often difficult to deposit due to their physical properties.
Challenges
Nanoparticles can be made of different materials such as metals, ceramics and polymers. The stability of nanoparticles can be an issue, as nanoparticles have a tendency to lower their very high surface energy, which originates from their high surface-to-volume ratio. Naked nanoparticles tend to be stabilized by sorption of molecules from the environment or by decreasing the surface area through coagulation and agglomeration.[1] The formation of these aggregates is generally undesirable. The tendency of a nanoparticle to coagulate can be controlled by modifying the surface layer. In a liquid medium, suitable ligand molecules are commonly attached to the nanoparticle surface as they provide solubility in suitable solvents and prevent coagulation.
Deposition methods
Contenido
Hay varios métodos de recubrimiento diferentes disponibles para depositar nanopartículas. Los métodos se diferencian por su capacidad para controlar la densidad de empaquetamiento de partículas y el grosor de la capa, la capacidad de utilizar diferentes partículas y la complejidad del método y la instrumentación necesaria.
Langmuir-Blodgett
In the Langmuir-Blodgett method, nanoparticles are injected at the air-water interface in a special Langmuir-Blodgett channel. The floating particles are compressed closer together with motorized barriers that allow the packing density of the particles to be controlled. After the particles are compressed to the desired packing density, they are transferred to a solid substrate by vertical (Langmuir-Blodgett) or horizontal (Langmuir-Schaefer) dipping to create a monolayer coating. Controlled multilayer coatings can be made by repeating the dipping procedure several times.[2].