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The dispersion process is used in various industries, including coatings, paper manufacturing, and food processing. All of these industries base their developments and technology of particle dispersion on theories that consider spherical particles in simple systems. The objective of this study was to improve understanding of the impact of these theories when applied to nonspherical/nonideal particles. Effective dispersion allows for a reduction in the use of the powder to achieve the specified final properties. This paper reports experimental results on the required energy (RE) used to disperse five different titanium dioxide (TiO2) samples into liquids with different values of surface tension [deionized (DI) water and DI water containing surfactants]. The selection of the TiO2samples was based on different particle sizes with the same surface properties, and similar sizes with different surface properties. The results showed that the particle shape is fundamental in determining the RE for dispersion, once it defines the number of interactions among the particles. The larger the number of interactions, the more energy is required to deagglomerate the particles. An empirical equation was developed to describe the energy required for pigment dispersion as a function of the ratio between the liquid and the particle surface tensions and the particle shape factor.

Wetting is the first step in the dispersion process of any powder. Understanding how the powder surface and the liquid properties affect the speed and intensity of the wetting process provides a set of tools to determine the dispersion efficiency as a whole, and an effective dispersion allows the reduced use of the powder to achieve the specified final properties. This article reports experimental results on the wetting behavior of five different TiO2samples by liquids with different values of surface tension [deionized (DI) water and DI water containing surfactants] and its effect on the dispersion process. The selection of the TiO2samples was based on different particles sizes with similar surface properties, and similar sizes with different surface properties. The samples were characterized in terms of their specific surface area and particle size distribution. The wetting behavior was evaluated by a capillary rise technique (Washburn) to measure liquid penetration height and rate, and the time evolution of the particle size distribution. The results show that larger particles presented faster wettability and that liquids with lower surface tension facilitate the wetting of the powder. The energy required to deagglomerate the powder is inversely proportional to the wetting speed: the faster the wetting the easier it will be to disperse the particles, with less energy required.