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A new Tabor's parameter ? is defined for adhesion-delamination of thin membranes. A small ? corresponds to a thick, small, and stiff membrane under the influence of a long-range weak surface force, as in the Derjaguin-Muller-Toporov (DMT) limit. A large ? corresponds to a thin, large, and flexible membrane under the influence of a short-range strong surface force, as in the Johnson-Kendall-Roberts (JKR) limit. A new adhesion map based on ? is drawn to summarize the "pull-off" events and the delamination trajectory for membranes under mixed stretching-bending deformation. Maps are generated for one- and two-dimensional membranes clamped at the edge. [ABSTRACT FROM AUTHOR]

The mechanical deformation of an ideal thin-walled cylindrical shell is investigated in the presence of intersurface interactions with a planar rigid substrate. A Dugdale- Barenblatt-Maugis (DBM) cohesive zone approximation is introduced to simulate the convoluted surface force potential. Without loss of generality, the repulsive component of the surface forces is approximated by a linear soft-repulsion, and the attractive component is described by two essential variables, namely, surface force range and magnitude, which are allowed to vary. The nonlinear problem is solved numerically to generate the pressure distribution within the contact, the deformed membrane profiles, and the adhesion-delamination mechanics, which are distinctly different from the classical solid cylinder adhesion models. The model has wide applications in cell adhesion and nanostructures. [ABSTRACT FROM AUTHOR]

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]