Dispersion Control of Al 2 O 3 Nanoparticles in Ethanol

It is quite difficult to handle a nanoparticle powder because of aggregation due to the high surface interaction between nanoparticles, which have a large specific surface area and high surface energy. Therefore, by using a dense suspension, the nanoparticle powder makes easier to disperse up to primary particles and to handle and facilitate transport and then that can produce its original performance. To obtain a homogeneous suspension with a high concentration and adequate fluidity, the aggregation and dispersion behavior of particles is usually controlled by using a polymer dispersant. However, there are some problems to produce a nanoparticle suspension using a polymer dispersant (Kamiya et al., 2003). For example: It is difficult to disperse a nanoparticle in a dense suspension with a high concentration because the distance between particles will be less than several nanometers and the particles will readily aggregate at the distance. As for a nanoparticle, the steric repulsion promotes a dominant dispersibility and stability in suspensions because the surface potential between nanoparticles is at least over 100 mV to disperse nanoparticles. The molecular size of a polymer dispersant with approximately several nanometers affects the dispersibility of nanoparticles in dense suspensions.