Random blisters on stickers: metrology through defects

Blisters are commonly observed when an adhesive sheet is carelessly deposited on a plate. Although such blisters are usually not desired for practical applications, we show through model experiments on angular blisters how material properties can be deduced from height profile measurements. In particular the typical curvature of the crests is found to be proportional to an elasto-capillary length that compares the bending stiffness of the sheet with the adhesion energy. In addition, the radius of the tip allows the estimation of the product of this length with the thickness of the sheet. The relevance of these results to realistic random configurations is finally confirmed.