Adhesion of a Cylindrical Shell in the Presence of DLVO Surface Potential.

A theoretical model is built for a micrometer size cylindrical shell adhering to a rigid surface in the presence of an electrolyte. In the presence of surface electrostatic double layers and van der Waals attraction according to the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the shell deforms and settles in either the primary (lmin) or secondary (2min) energy minimum depending on whether it has sufficient energy to overcome the repulsive energy barrier. The adhesion-detachment mechanics are constructed and solved computationally, yielding the relations between applied load, deformed profile, and mechanical stress distribution in the shell. The critical compressive load needed for transition from 2min to lmin is found for several repulsive barrier heights. At a critical pull-off tensile force, shell in the lmin detaches spontaneously at a nonzero contact area, but the one in the 2min detaches smoothly with the contact shrinking to a line contact. The model is relevant to bacterial adhesion in environmental engineering and microelectromechanical systems for microfluidics applications. [ABSTRACT FROM AUTHOR]