pigmentdispersion

Pigment dispersion is the process of distributing pigment particles throughout a medium so that they form a uniform, stable suspension. In industrial settings this is essential for paints, inks, plastics, cosmetics, and coatings, where dispersion affects color strength, opacity, and rheology.

Dispersion is achieved by mechanical action such as ball or bead milling, high-shear mixing, and ultrasonication, often with dispersants or surface treatments to improve wetting and prevent reaggregation. Key factors include particle size and shape, surface chemistry, charge, solvent or vehicle polarity, and the viscosity of the medium. Stabilization can be electrostatic, steric, or a combination (electrosteric).

Stability challenges include sedimentation, sediment compaction, flocculation, and color drift. Quality control relies on particle-size analysis, microscopy, colorimetric measurements, and rheology tests to ensure homogeneity and performance over time.

Applications span coatings, printing inks, plastics, cosmetics, and ceramics.

In ophthalmology, pigment dispersion describes the release of pigment granules from the iris pigment epithelium, which can lead to pigment dispersion syndrome and pigmentary glaucoma. Diagnosis involves slit-lamp examination and gonioscopy; treatment focuses on monitoring and managing intraocular pressure to prevent optic nerve damage.