I meet the similar carck problem. My project is about the silica gel thin film-chemical modified electrode(CME). I've tried TEOS and (3-Aminopropyl)trimethoxysilane (APTMOS). I find that APTMOS gel film is not easily cracked. But the APTMOS gel is dissolvable in the aqueous solution!!! Due to the basic nature of APTMOS, no additional base was added in my experiment. I wonder why My APTMOS gel is dissolvable in the aqueous solution and how to prevent it. Thanks a lot!