Disk drive comprising a spindle motor employing anionic/cationic lubricant to reduce disk surface potential

A spindle motor for rotating a disk in a disk drive, the disk drive comprising the disk and a head actuated over the disk;

• the spindle motor comprising:
• (a) a rotating component;
• (b) a stationary component;
• and
• (c) a first and second bearing assembly disposed between the rotating component and stationary component for rotating the rotating component about the stationary component, wherein:
• the rotating component for attaching to the disk;
• the first bearing assembly comprises a first stationary component surface and a first rotating component surface;
• an anionic lubricant is disposed between the first stationary component surface and the first rotating component surface such that a first voltage forms between the first stationary component surface and the first rotating component surface when the rotating component rotates about the stationary component;
• the second bearing assembly comprises a second stationary component surface and a second rotating component surface;
• a cationic lubricant is disposed between the second stationary component surface and the second rotating component surface such that a second voltage forms between the second stationary component surface and the second rotating component surface when the rotating component rotates about the stationary component;
• and
• a polarity of the second voltage being opposite a polarity of the first voltage to thereby reduce the potential at the disk surface.