We report the formulation of sol-gel derived GeO2 and GeO2-SiO2 core-shell colloidal suspensions for use as feedstocks in direct ink write (DIW) 3D printed glass optics. Germania-silica or GeO2-SiO2 colloidal feedstocks are of interest because silica-germania glass exhibits similar physical and optical properties of traditional silica glass, but with reduced wavefront error or scatter loss. Additionally, the refractive index of SiO2-GeO2 can be readily tuned by proportionally increasing the amount of Ge-dopant. While existing reports of sol-gel GeO2 particle formulations do exist in the literature, there is no comprehensive investigation that accounts for the combination of factors important for use as DIW glass feedstocks. As a result, we have surveyed a wide range of reaction conditions (i.e., H2O, catalyst, and temperature) to determine the optimal sol-gel GeO2 particle formulation. Optimization was evaluated by studying particle size, shape, and morphology using DLS and TEM. From our optimized GeO2 sols, we have also identified multiple pathways to prepare core-shell GeO2-SiO2 particles of various shapes and sizes as shown by TEM. We have also demonstrated proof-of-concept that these particles are viable DIW glass feedstocks. Ongoing research includes studying the chemical characterization of the core and core-shell particles at various stages of particle growth and glass formation.

Tuning sol-gel GeO2 and core-shell GeO2-SiO2 reaction conditions to optimize particle properties for use in 3D printing glass optics

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.