||Electrospun nanocomposite is considered as one of the most highly researched areas in nanomaterials by the virtue of their improved mechanical properties, dimensional stability, thermal/chemical stability. Poly(ethylene oxide) (PEO) is a polyether compound with many applications from industrial manufacturing to medicine or functional materials. PEO can be crosslinked by γ and UV irradiation, but few reports have been made concerning the chemical crosslinking of this important and versatile polymer. In this study, we demonstrated electrospun sheets composed of PEO crosslinked with TEOS (tetraethoxy orthosilicate) by post-exposure to acid vapor. The high stability of the TEOS-reinforced fiber matrix resulted from the chemical crosslinking between hydrolyzed TEOS and PEO. Finally, we prepared “turn-off” system based on silica-reinforced electrospun PEO sheets embedded with conjugated polymer owing to fluorescence quenching by acid.