Macroporous thin films for planar chromatography

A procedure for the preparation of macroporous silica films suitable for planar chromatography is described. The films are produced by a low pH catalyses of alkyltrialkoxysilanes in oversaturated solution of pore forming organic compounds. A segregated three phase system yields thick films (10–60 µm) that have good adhesion to silica glass supports, uniform, mirror like surface and intercalated micron-dimension pores that permit capillarity driven elution of solvents through the film. A phase diagram demonstrating optimal operating conditions for macroporous and microporous film formation is introduced and analyzed.