The use of microplasmas is being looked into for the synthesis of complex macromolecules, as well as the addition of functional groups to the surfaces of other substrates. An article by Klages et al. describes the addition of amino groups to the surfaces of polymers after treatment with a pulsed DC discharge apparatus using nitrogen containing gases. It was found that ammonia gas microplasmas add on an average of 2.4 amino groups per square nanometer of a nitrocellulose membrane, and increase the strength at which the layers of the substrate can bind.