Modification of stearic acid in Ar and Ar-O2 pulsed DC discharge
| Autor: | Bernardelli,Euclides Alexandre, Souza,Thiago, Mafra,Márcio, Maliska,Ana Maria, Belmonte,Thierry, Klein,Aloisio Nelmo |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | Materials Research, Vol 14, Iss 4, Pp 519-523 (2011) Materials Research, Volume: 14, Issue: 4, Pages: 519-523, Published: 14 OCT 2011 Materials Research v.14 n.4 2011 Materials research (São Carlos. Online) Universidade Federal de São Carlos (UFSCAR) instacron:ABM ABC ABPOL |
| ISSN: | 1516-1439 |
| Popis: | Stearic acid (CH3(CH2)16COOH) was treated with Ar and Ar-O2 (10%) pulsed DC discharges created by a cathode-anode confined system to elucidate the role of oxygen in plasma cleaning. The treatment time (5 to 120 minutes) and plasma gas mixture (Ar and Ar-O2) were varied, and the results showed that the mass variation of stearic acid after Ar-O2 plasma exposure was greater than that of pure Ar plasma treatment. Thus, compared to Ar*, active oxygen species (O and O2, in all states) enhance the etching process, regardless of their concentration. During the treatments, a liquid phase developed at the melting temperature of stearic acid, and differential thermal analyses showed that the formation of a liquid phase was associated with the breakage of bonds due to treatment with an Ar or Ar-O2 plasma. After treatment with Ar and Ar-O2 plasmas, the sample surface was significantly modified, especially when Ar-O2 was utilized. The role of oxygen in the treatment process is to break carbonaceous chains by forming oxidized products and/or to act as a barrier again ramification, which accelerates the etching of stearic acid. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|