He+O2+H2O plasmas as a source of reactive oxygen species

The effect of water in the chemistry of atmospheric-pressure He+O-2 plasmas is studied by means of a comprehensive global model. Water enables the generation of reactive oxygen species (ROS) cocktails that are rich not only in O, O-2*, and O-3 but also in OH and H2O2. Due to its polar nature, water also leads to cluster formation, possibly affecting the plasma dynamics. Since the lifetime of many of the ROS is short, the plasma chemistry plays two roles: (i) direct interaction with superficial cells and (ii) triggering of a secondary chemistry that propagates the plasma treatment to regions away from the plasma-surface interface. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3592775]