Embodiments of the invention include articles comprising a diamond like carbon coating or doped diamond like carbon coating on one or more surfaces of a plastic substrate or a plastic enclosure. Embodiments of the DLC or doped DLC coatings reduce the gas permeation of the coated plastic or thermoplastic to hydrogen or helium compared to the permeability of the plastic alone. The DLC or doped DLC coatings coating provides a surface resistivity of from about 107 to about 1014 ohm/square and have a transmittance that range from about 0% to about 70% less than the transmittance of the underlying plastic substrate in the range of about 300 nm to about 1100 nm. The DLC coated plastic can be used in environmental enclosures for protecting environmentally sensitive substrates such as semiconductor wafers and reticles.