Effect of the polysilane structure on its solution fluorescence quenching

We studied the solution fluorescence quenching of poly(methylphenethylsilane) (1^#), poly(dimethylsilane‐co‐methylphenethylsilane) (2^#), poly(n‐hexylmethylsilane) (3^#), and poly(dimethylsilane‐co‐n‐hexylmethylsilane) (4^#) by such quenchers as CCl₄, CHCl₃, Cl₂CHCHCl₂, and methyl benzoate. We treated the fluorescence quenching data using the equations F₀/F = 1 +K_SV[Q],F₀/F exp(−NV[Q]) = 1 +K_SV[Q], and ln(F₀/F) =NV[Q], where F and F₀ are the fluorescence intensity with and without the addition of a quencher, respectively; K_SV, the Stern–Volmer constant; [Q], the quencher concentration; N, Avogadro's constant; and V, the volume of the active sphere. For the systems with both static quenching and dynamic quenching, we calculated their contributions and the critical quencher concentration [Q]_C and determined the nature of the fluorescence quenching in different quencher concentration ranges. We observed that, under the condition of the same quencher, the fluorescence quenching of the polysilane homopolymer is smaller than that of its corresponding polysilane copolymer, that is, 1^# < 2^# and 3^# < 4^#, and that for the fluorescence quenching of the same polysilane by different chlorohydrocarbons the fluorescence quenching ability of CCl₄ is larger than that of CHCl₃ and Cl₂CHCHCl₂. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 133–139, 2000