Unbalanced AC field

Aperiodic electrophoresis refers to the use of an unbalanced AC field to separate charged polarizable particles due to the Stotz-Wien effect of field-dependent electrophoretic mobility. 

In principle, the Stotz-Wien effect can be used to separate colloidal particles using an unbalanced AC field, which has zero time average (E) = 0, but nonzero time-averaged higher moments, such as (E )/=0. An unbalanced AC field leads to a size-dependent nonlinear... 

The first experiments demonstrating field-dependent electrophoretic mobility of colloids (Stotz-Wien effect) were reported by several groups in the 1970s [14], and the possibility of using this effect for particle separation using unbalanced AC fields has begun to be explored [14]. This work focused on nonlinear corrections to the classical phenomenon of electrophoresis, where a particle moves in the direction of the applied electric field, U = b(E)E, rather than on the associated ICEO flows and more complicated ICEP motion. 

A periodic alternating-current (AC) electric field is called unbalanced if its first moment has zero time average (( ) = 0), but at least one of its higher moments does not (e.g., (E ) 0). 

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