Measuring of the hardly measurable: adhesion properties of anti-adhesive surfaces

Adhesion is a universal phenomenon influencing many processes in natural and technical systems. To elucidate these influences, reliable measurements of adhesion forces are of high importance. In the present study, by using a microforce tester combined with a compliant sticky probe, we introduce a newly established method allowing adhesion measurements on surfaces with low adhesive capabilities. Four quality control tests revealed a high reproducibility and reliability of data obtained. Further advantages of the method are (1) defined geometry of the probe, (2) ease attachment of the probe to the cantilever, (3) its applicability for time consuming experiments, (4) as well as a low price of components and a minimum of required equipment. We present the first results obtained by using this method in a case study with six epoxy resin replicas having various roughness (R (a) =0.007-3.515 mu m). Interestingly, the highest pull-off force values were obtained not on the smooth sample, but on the surface with the finest microroughness (R (a) =0.150 mu m). With a further increase in the surface microroughness, pull-off forces continuously decreased. These results are in accordance with previously reported theoretical predictions.