Substituent effect on the fluorescence quenching of polystyrene derivatives by polymeric plasticizers

The fluorescence quenching of poly (4-methylstyrene), poly (4-methoxystyrene), poly (α-methylstyrene) and poly (4-tert-butylstyrene) by dimethyl terephthalate, diethyl terephthalate, dibutyl phthalate and dioctyl terephthalate has been investigated in solvent of different polarities. Fluorescence spectra of these derivatives reveal the presence of both monomeric and excimeric emissions in all used solvents and were affected by the type of substituent and the polarity of the solvents. Monomeric and excimeric emissions were quenched by the addition of plasticizer as electron donors and quenching efficiency was affected by the polarity of solvents as well as the molar mass of the added plasticizer. As a result of the quenching processes no exciplex emission was observed in all used solvents. Quenching parameters such as quenching rate constants and quenching cross-sections for these quenching processes were calculated in all used solvents.