Polymers may also be adsorbed to surfaces through polyelectrolyte adsorption. In gas adsorption, nitrogen at its boiling point is adsorbed into the aerogel sample. Gaseous molecules cannot be readily adsorbed onto graphene surfaces, so intrinsically graphene is insensitive. Specifically adsorbed, partially solvated ions appear in this layer. The gaseous compounds may be adsorbed on the surface of the aerosol particles. Self-assembled monolayers can also be adsorbed from the vapor phase. Being lipophilic, Mirex is strongly adsorbed on sediments. The absorbed molecule is adsorbed onto a surface into a precursor state. These soot particles also carry carcinogens like benzopyrenes adsorbed on their surface. Pseudocapacitance can originate when specifically adsorbed ions out of the electrolyte pervade the double-layer. Contaminants are adsorbed onto the cellular structure. This method is useful for studying vibrations of molecules adsorbed on a solid surface. He called ions in direct contact with the electrode "specifically adsorbed ions". Active stirring ensures the PVP has adsorbed to the nanoparticle surface. The inner Helmholtz plane (IHP) passes through the centres of the specifically adsorbed ions.