Thin films (e.g. diamond-like films) and coatings (e.g. polymeric coatings) are commonly applied on biomedical devices to achieve desired performance and functionality such as biocompatibility and durability. The adhesion of a film or coating to the substrate is a fundamental attribute for any intended application. Adhesion measurement of films and coatings thus is very crucial in biomedical applications.
Mechanical test methods dominate adhesion measurement for biomedical applications, which include the peel test, the scratch test, the pull-off test, the blister test, the micro-indentation test, the small punch test, the edgedelamination test, and the four-point bend test. The correlation between the nominal adhesion parameter (practical adhesion) and the intrinsic or fundamental adhesion in most of these tests is explained.
Although a plethora of techniques exists for practical adhesion measurement of films and coatings, in this review we have discussed only those techniques which have been already employed or offer potential for use in biomedical applications.
Key words: Adhesion measurement, fundamental adhesion, practical adhesion, films coatings, fracture mechanics, coatings for biomedical devices