Ion Mobility Measurements in a 50 cSt Viscosity Polydimethylsiloxane Silicone Oil

Using two different time-of-flight techniques (pulse voltage and V.U.V. photon pulse) ion mobility measurements ents have been performed, at room temperature, on a purified 50 cSt polydimethylsiloxane silicone oil (Rhône Poulenc 604 V 50). These experiments have been carried out in a cell with planparallel electrodes, for electric field strengths ranging from 0.4 to 10 kV cm-1 and for four electrode gaps (0.15, 0.19, 0.22 and 0.3 cm). The effect of additives such as N2O and C7F14 has also been investigated. The positive ion mobilities (27.5xl0-5 cm2V-ls-1) are independent of the additives while the negative ion mobilities decrease from 7.3x 10-5 cm2V-1s-1 under N2 to 5.3x10-5 cm2V-1s-1 in the presence of C7F14.