Fluid oscillations on structured surfaces

A method of manufacturing a device, comprising:

• forming a first electrical insulating layer on a substrate;
• removing portions of said first electrical insulating layer and portions of said substrate to form a conductive base layer and a plurality of fluid-support-structures, each of said fluid-support-structures having at least one dimension of about 1 millimeter or less and said first electrical insulating layer thereon;
• and
• forming a second electrical insulating layer on sides of said fluid-support-structures, said conductive base layer being substantially devoid of said first and second electrical insulating layers.