Light-scattering efficiency of white pigments: an analysis of model core - shell pigments vs. optimized rutile {TiO2}

Robert W. Johnson, Erik S. Thiele, French RH.  1997.  


The light-scattering efficiency of a white pigment is strongly dependent on its re-fractive index and particle size. Rutile {TiO} 2 is an effective opacifier because of its high refractive index. Its efficiency can be further optimized by generating narrow particle size distributions near the optimum diameter. Recently, an al-ternative core - shell pigment was pro-posed as a means of increasing the light-scattering efficiency of {TiO} 2 {.The} proposed hybrid pigment would be pre-pared by coating a shell of titania on spherical silica particles or some other low-refractive-index {material.Theoretical} calculations of the light-scattering effi-ciencies of these core - shell particles and solid {TiO} 2 particles show that core - shell particles are substantially less efficient light-scattering materials than pure rutile, especially in the do-main of titania coating thickness that can be realistically applied to a core material.


{TAPPI} Journal





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