Design of new lanthanide pH switches based on a cross-linked poly(vinyl alcohol)/tetraethoxysilane hybrid matrix

The design and synthesis of cross-linked siloxane and polymeric matrices incorporated with terbium or europium complexes have been studied. The preparation of hybrid hosts demonstrated that poly(vinyl alcohol) in the presence of tetraethoxysilane with various concentrations gave different mechanical stabilities and water solubilities. The as-derived films exhibited excellent photophysical properties of lanthanides with large Stokes shifts, narrow emissions, and high color purity. It has been found that the luminescent materials were dramatically quenched over the assayed pH ranges (pH 7 to 1 and pH 7 to 14). These optical probes could be recycled for ten times by changing the aqueous media. The novel inorganic-organic responsive films that can be switched on or off based on pH values will find potential application in biological analysis.