[3PS-152]
Decoupling the Colloidal Dispersion Stability and Optical Efficacy of Titania Sunscreens: A Rheology-Holography Framework
발표자장다겸 (포항공과대학교)
연구책임자이기라 (포항공과대학교)
Abstract
Mineral sunscreens are governed by dispersion of inorganic UV filters. Even with surface treatment, agglomeration and phase separation facilitate heterogeneous films, leading to white cast, non-uniform film coverage and degraded optical integrity. Despite industrial surface functionalization, it remains a challenge to detect kinetic stability by visual inspection. Here, we quantified ligand-mediated kinetic stability of TiO2 suspensions aged for 12 weeks, comparing three TiO2 samples bearing distinct surface functionalizations. Dynamic oscillatory rheology within the linear viscoelastic region tracked viscoelastic moduli evolution. In-line holographic video microscopy measured aggregate size, refractive index and estimated porosity via Lorentz-Lorenz. Mixed-ligand TiO2 was most stable yet gave lowest SPF, indicating decoupling: packing density and porosity can reduce UV attenuation. Rheology-holography-in vitro SPF testing provides a robust predictive platform.