The effects of storage gases on the durability of ammonia plasma effects with respect to wound fluid absorption and the biostatic activity of viscose non-wovens

Non-woven viscose samples were treated for 5 min with non-equilibrium ammonia plasma. Plasma-induced properties often gradually change with time, thereby limiting the durability of surfaces for industrial application. The modified samples were stored for 10 and 30 days under air and argon, i.e. possible gases for maintaining plasma-gained absorption kinetics and biostatic activity. XPS results for the aged samples showed practically the same composition as for the freshly-treated samples, regardless of storage gases. Any aging of the plasma-induced hydrophilicity was not evident as the absorbency rate, capacity, and contact angles remained almost unchanged within one month, independent of the storage gases used. Biostatic activity endured almost unaltered over 10 days, whereas it decreased during 30 days, being more pronounced within argon than air. The results from absorption kinetics for both the saline solution and the synthetic exudate, as well as from microbiological analyses, revealed that the plasma-induced modifications of the non-woven material remained fairly unaltered for at least one month when stored within air, thus making this technique attractive for wound dressing applications.