I work for a publishers http://xnxx-xnxx.site/ xnxxphotos Unfortunately pure, undamaged graphene is impermeable to all gases, because its atoms are surrounded by dense electron clouds. But graphene is difficult to manufacture, and samples almost always contain defects, such as holes, tears and grain boundaries, through which gas molecules could, in principle, seep. Even more defects can be introduced into graphene if it is reacted with an acid to produce graphene oxide, in which some of the carbon–carbon bonds are broken to re-form with oxygen atoms.