Growth of SiO₂ Needles Induced by Positive Corona Discharging

Growth of needles induced by positive discharging in air containing a small amount of dimethyl-poly-siloxane (DMPS) vapor was examined. After discharging for 30 to 120 minutes in pure air containing DMPS vapor, amorphous SiO₂ needles and a thin film had grown on tungsten wire anode. The needles had a hollow tube running parallel to the axis of each needle. In contrast, needles grown in just pure air contain tungsten. The growth of needles caused by plasma oxidation of DMPS and by sputtering of the tungsten wire anode owing to negative ion impinging is discussed.