  A simple and robust electrode insulation technique that can withstand a
voltage as high as $\mathrm{1000~V}$, which is equivalent to an electric field
strength of $\sim 1MV/m$ across a $\mathrm{10~\mu m}$ channel filled with an
electrolyte of conductivity $\sim 0.1~S/m$, i.e., higher than sea water's
conductivity, is introduced. A multi-dielectric layers approach is adopted to
fabricate the blocked electrodes, which helps reduce the number of material
defects. Dielectric insulation with an exceptional breakdown electric field
strength for an electrolyte confined between electrodes can have a wide range
of applications in microfluidics, like high electric field strength-based
dielectrophoresis. The voltage-current characteristics are studied for various
concentrations of sodium chloride solution to estimate the insulation strength
of the proposed materials, and the breakdown strength is calculated at the
point where the electrical insulation failed. A detailed adhesion technique is
also demonstrated, which will reduce the ambiguity around the fabrication of a
sealed channel using SU-8.
