Quantitative adhesion test for thin films using a Vernier force sensor

Abstract

Of the four mechanical properties of thin films (stress, adhesion, hardness and stiffness) adhesion is the most difficult to measure. Conventional thin film adhesion tests can be as simple as a "scotch tape" method where an adhesive tape is pressed on the film and removed and the film is evaluated to be wholly, partially or left behind. Quantitative methods exist but are usually carried out under special conditions or using complicated apparatus. In this paper, we propose a simple quantitative adhesion test similar to the dolly pull-off adhesion test using a force sensor included in the Universal Laboratory Interface (ULI) Physics with Computers kit from Vernier Software. It is being developed primarily to characterize evaporated films on substrates at the Materials Physics laboratory at the Ateneo de Manila University but can be applied to a wide variety of samples. Since the force sensor is interfaced to a computer, force measurements are fully automated and can handle up to 30,000 data points.