ENERGY-TRANSFER STUDIES WITH FLUOROSILOXANES

Four fluorinated siloxane polymers labeled with fluorescent dyes were prepared by hydrosilylation of a mixture of allyl ethers with poly(met hyl hydrogen siloxane). These comprised n-octyl allyl ether, 1H,1H,2H, -2H-perfluorooctyle allyl ether, and either 9-phenanthrylmethyl allyl ether or 9-anthrylmethyl ether. In addition a non-fluorinated polymer was prepared with the octyl allyl ether plus the phenanthryl ether, Th ese yielded five polymers, mutually immiscible liquids labeled with ch romophores appropriate for energy transfer studies. These experiments were carried out in 1,1,2-trichloro-1,2,2-trifluoroethane solution. Fl uorescence decay profiles for the phenanthrene were ail exponential, w ith lifetimes of 25 nsec for the allyl ether and 30 nsec for the polym er bound chromophore. Quenching was diffusion controlled, as expected; and the polymer-polymer reaction had a rate 5-fold slower than that b etween the phenanthryl and anthryl allyl ethers, independent of the fl uorocarbon content of the polymer.