Determination of Hansen solubility parameters of particles using a capillary penetration method

Hansen solubility parameters (HSPs) are useful to evaluate the compatibility of functional particles in a liquid phase. Until now, sedimentation velocity and dynamic light scattering (DLS) methods have been used to measure the HSPs of particle surfaces. However, determination of HSPs of highly dense materials and large or nonspherical particles by these methods is difficult. In this study, we used a capillary penetration method to determine the HSPs of a fine particle surface. We confirmed the effectiveness of the capillary penetration method by measuring the HSPs of the surface of spherical silica particles with a diameter of 1 mu m. The HSPs determined by the capillary penetration and DLS methods were similar. The capillary penetration method developed in this work will enable simple measurement of the HSPs of dense and large particles, which will facilitate future applications of such particles.