Agglomeration and distribution of nanoparticles One can classify the agglomeration nanoparticles in two ways: soft or hard. Most of the soft agglomeration occurs due to electrostatic interactions between particles, as well as van der Waals forces. The weak force allows soft agglomeration to pass certain chemical tests. Use of mechanical energy, or the law, to exterminate; formation of hard aggregates. In addition to the van der Waals and electrostatic forces, there is also chemical bonding. Therefore, hard agglomerates, while not simple to defeat, require special control methods.

Schematic diagram showing the aggregate of nanoparticles

The van der Waals effect or interaction between the groups is one of the ways to prevent nanoparticles from forming hard-block precipitates. It allows the primary particles not to agglomerate to create secondary particles. This causes the formation of hard-blocked precipitates with high densities. The anti-agglomeration mechanism is broken down into the following: (1) electrostatic stabilizement (DLVO theory);(2) steric stabilitization; and (3) electrostatic steric stable.

Electrostatic stabilizement mechanism (DLVO theoretical)

By adjusting pH to form an electric double, the electrostatic stabilization system, also known by the electric layer stabilization scheme, produces a surface charge. Repulsive forces in between the electric double layer reduces the attraction between the particles and allows the nanoparticles to disperse. Figure 2 illustrates the mechanism.

Stochastic stabilization mechanism

Steric stabilization works by adding uncharged particles of polymer compound in suspension. The nanoparticles are then adsorb this substance around them to create microcell states. Figure 4 depicts the mechanism diagram.

Electrostatic steric stabilization mechanism

The Electrostatic stability mechanism is a combination the first two. That is, it involves the addition of a specific amount of polyelectrolyte into the suspension to adsorb that polyelectrolyte at the surface of the particle. The pH value of polyelectrolyte is maximized to increase the dissociation rate of polyelectrolyte. Thus, when the polyelectrolyte near the particle surface reaches saturated absorption, both of them work in concert to uniformly disperse the particles. Figure 3 depicts the mechanism diagram.

Nanoparticle dispersion method

There are three phases to the dispersion process for nanoparticles. First, liquid wetting is used to dissolve the solid particles. Second, external forces disperse larger particles into smaller ones. Third, stabilization of particles occurs. This ensures that dispersed particles do not re-aggregate. It is possible to divide it according to the different dispersion mechanisms into surface modification method and mechanical action method.

The mechanical action technique refers the use or the apparatus to increase dispersion stability. To ensure that nanoparticles are evenly distributed within the medium, mechanical agitation dipersion can be described as a straightforward physical dispersion. This method uses only mechanical energy like external shear or impact force. Ultrasonic dipersion occurs when ultrasonic cavitation generates local high temperatures, high pressures or strong shock waves and microjets. This can reduce nano-action energy and stop nanoparticles becoming agglomerated and completely dispersing.

Modification

Inorganic substances modify the surface of nanoparticles Inorganic substances are uniformly applied to the nanoparticle’s surface. To decrease its activity and stabilize the inner one, the active group of the hydroxyl on the surface is shielded. Because the chemical reaction between inorganic matter, nanoparticle surface, is not easy, the modified nanoparticle and the modifier are dependent on van der Waals force.

Surface modifications of nanoparticles using organic matter

Inorganic nanoparticles can be organically coated by using functional groups within organic molecules. The coating allows for the surface to be chemically modified or to absorb the functional groups.

conclusion

This edge discipline is related to many others, including organic and colloidal chemical chemistry as well as modern instrument analysis. A surface coating modification technique has been extensively used in the area of surface modification for nanometers. Additionally, the research results indicate that the technology’s future prospects are good. However, it is still difficult to determine the exact modification mechanism and method, as well the equipment required for this purpose, or the characterization of modification effects. This is a problem that cannot be fixed fundamentally. Further research is essential. A nano surface modification technique is an essential tool to generate new materials. Research and development in nano-particles is ongoing. Further exploration into the surface modification of nanopowders will be a key part of the future of nanotechnology. The economic and other benefits. Cie-Chinaadvanced metal Tech Co., Ltd., (Lemondedudroit), has more 12 years experience in chemical product development. Contact us to receive high quality Zinc Nanoparticles.
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