A template-free, more environmentally friendly approach for glass micro-texturing.

Micron and nanometer size textured silicate glass surfaces are of interest in consumer electronics, photovoltaics, and biosensing applications. Typically, texturing glass surfaces requires applying a patterned mask or a pre-etching treatment (e.g. sandblasting) on the glass substrate, followed by a mask transferring or etching process using a fluoride-containing compound. The major challenges of such a process are the complexity and cost of masking, and the safety and environmental concerns around the usage and disposal of hydrofluoric acid. Here, we describe a template-free method to construct micron-sized and submicron-sized texture on isotropic glass surfaces in one step. The new texturing mechanisms are well supported by experimental data and peridynamic simulations. With this novel strategy, the etchant uses fluoride-free chemicals such as citric acid to texture silicate glass. Etchant concentration, etch temperature, time, and additives are the primary parameters that dictate the texturing process. Surface feature size and depth can be independently controlled by tuning the leaching and chemical polishing process. We hope this study can trigger more research on novel and more environmentally friendly texturing of isotropic materials.

Constructing surface models of silicate glasses using molecular dynamics to understand the effect of pH on the hydration properties.

In this work, we use realistic silicate glass surface models, with molecular dynamics simulations, and present an algorithm for proper atomic partial charge assignment, consistent with measurable internal dipoles. The immersion energy is calculated for different silicate glass compositions in solutions of varying pH. We use molecular dynamics to elucidate the differences in the structure of water between mono- and divalent cations. The immersion energy of the glass surface is found to increase with an increase in ionic surface density and pH. This can be attributed to the stronger interaction between water and cations, as opposed to the interactions between water and silanol groups. The developed models and methods provide new insights into the structure of glass-solution interfaces and the effect of cation surface density in common nanoscale environments.