Foam Silica Films Synthesized by Calcium Chloride-Assisted Emulsification

The development of porous films with an accessible high specific surface area is important for designing new adsorbents, sensors, or catalyst supports. Here, we describe a simple method to prepare silica foam coating using calcium chloride-assisted evaporation-induced emulsification method. An alcoholic sol containing chloride and poly(ethylene oxide)-based polymer deposited on substrate by dipping. evaporation the alcohol induces phase separation between silica-rich calcium-rich one. size droplets increases via coalescence process until gelation sol, which determines final pore 100 nm 3 μm. Thermal analysis monitoring droplet confirm that departure solvent delayed presence in sol. influence nature porosity discussed. use block copolymer such as Pluronic F-127, strongly stabilizes emulsion, allows reach low (400 nm), while contrary, propose short glycol) (PEG) PEG-400, weakly it, leading larger pores (2-3 μm). Furthermore, show addition zirconium salt (ZrOCl2·8H2O) accelerates condensation step leads decrease size.