On the measurement of “tack” for adhesives

Abstract

One of the tests for determining the bond strength of adhesives involves measuring the force or the work required to pull apart two surfaces separated by a thin film of adhesive. The pull-off force is measured via the bending of a cantilever that connects one of the surfaces to a motor controlled vertical traverse. Although such tests are routinely performed, little attention has been paid to the understanding of force measurements and their relation to the dynamics of the instrument. Specifically, the measured force versus gap profile for the pull-off process is different from that measured when the same adhesive is compressed between two approaching surfaces. Through experiments on Newtonian liquids and a simple analysis involving lubrication analysis of thin liquid films, we show that the hysteresis in measurements results from a combination of an instrument-related instability and the nucleation and collapse of cavitation bubbles in the flow field.

Experimental Analysis of Prepreg Tack

“…[13], by Poivet and coworkers in ref. [14] but has also been observed by Tirumkudulu and coworker [15]. It should be noted that this phenomenon was observed even if the probe is stopped during the cavity extension phase.…”

Controllable adhesion using field-activated fluids

“…Adhesive tensile tests are performed by separating the two disks at constant (apparent) speeḋ h A , and the resulting force curves are measured. The apparent separation h A is related to the true separation h via the instrument compliance [2], as outlined in Appendix A. The adhesive force predictions of Eqs.…”

“…The Texture Analyzer is known to exhibit finite compliance in the loading direction which can cause experimental artifacts under certain adhesive test conditions [2]. For our setup the system stiffness was measured to be S = 0.124 N/µm (Compliance 1/S = 8.08µm/N).…”

Computer simulation of viscous fingering in a lifting Hele-Shaw cell with grooved plates

“…Viscous fingering in the lifting Hele-Shaw cell (LHSC) is now a widely studied problem [1][2][3][4], because of its academic interest and also due to its application in practical problems such as adhesion [5,6].…”