Comparison between micro-objects manipulations in dry and liquid mediums

In the submillimetric objects manipulations, the adhesion (capillary force, pull-off force and Van-der-Waals force) and the electrostatic forces affect the behavior of the micro-objects. These forces decrease significantly when the micro-objects are submerged in a liquid medium. So a microassembly task is easier to perform in a submerged medium than in air. Consequently, the study of the micro-objects assembly automation in liquid mediums is a promising topic. This article introduces a review of the major differences between dry and submerged micromanipulation. The influences of the medium on electrostatic forces, pull-off force and hydrodynamic forces are presented. Adhesion perturbations are significally reduced in liquid and hydrodynamic forces are advantageous to limit the maximal micro-objects velocity. Some comparative experimental micromanipulations are described and prove the interest of the liquid medium.