Is HF really necessary? Revisiting silica etching protocols in particle brushes

Particle brushes are an emerging type of hybrid polymer material at present, among which the polymer brush with silica as the core is a the most common type. Normally, hydrofluoric acid is used to etch these particles prior to chromatographic analysis, but hydrofluoric acid is particularly hazardous to humans and the environment. Herein we reports the use of NH4HF2 instead of hydrofluoric acid for the etching process and is extended to particle brushes with other inorganic cores such as barium titanate.