Pinned state in a two-dimensional soap froth

Experimental results of the pinning state of a two-dimensional soap froth are herein reported. In the current literature there are some results concerning the pinning of grain boundaries by a periodic array of pinning centers. The present work details with a random array of pinning centers, a more realistic situation also related to the metallurgical problem of grain boundary pinning in polycrystalline materials (Zener pinning). Current trends in the theoretical comprehension of this phenomenon are analyzed. Our results show that the cell size scales as f^-0.5 in the stagnated state, the area fraction of pinning centers being f.