Abstract Introduction of polar oxygen functional groups into carbon surfaces by plasma treatment results in dramatic changes in their wettability and electronic properties. Herein, we propose the combined theoretical and experimental approach to explore the chemical nature and stability of these functionalities. The DFT calculations were performed to evaluate the value and direction of the formed surface dipoles of Csurf−OH, −CHO, –COOH, =O, Csurf-O-Csurf moieties, whereas the surface-sensitive techniques (XPS, SIMS), allow for their identification. The evolution of functionalization was monitored in time by the means of changes in wettability (water contact angle) and electrodonor properties (work function measured by Kelvin method). The results show that ∼6 at.% of surface oxygen (−OH, −CHO, –COOH), led to dramatic changes in work function (increase by 1.15 eV) and water contact angle (decrease by 74°). The evolution of surface functionalization was systematically monitored over the period of 60 days after plasma treatment. Both, electronic properties and wettability tended to recover over time. SIMS depth profiling clearly illustrate changes in surface composition of the aged graphenic surfaces, which were below the XPS sensitivity. Since plasma treatment is often used as the first step in the surface properties tuning of carbon materials, the practical importance of immediate functionalization after activation is highlighted.

中文翻译：

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氧功能化石墨烯表面的稳定性：对电子特性和润湿性的理论和实验见解

摘要 通过等离子体处理将极性氧官能团引入碳表面，导致其润湿性和电子特性发生巨大变化。在这里，我们提出了理论和实验相结合的方法来探索这些功能的化学性质和稳定性。执行 DFT 计算以评估 Csurf-OH、-CHO、-COOH、=O、Csurf-O-Csurf 部分形成的表面偶极子的值和方向，而表面敏感技术（XPS、SIMS）允许以供他们识别。通过润湿性（水接触角）和电供体特性（通过开尔文方法测量的功函数）的变化及时监测官能化的演变。结果表明，~6 at.% 的表面氧（-OH、-CHO、-COOH），导致功函数（增加 1.15 eV）和水接触角（减少 74°）发生巨大变化。在等离子体处理后的 60 天内系统地监测表面功能化的演变。随着时间的推移，电子特性和润湿性都趋于恢复。SIMS 深度分析清楚地说明了老化石墨烯表面的表面成分变化，其低于 XPS 灵敏度。由于等离子体处理通常用作碳材料表面性能调整的第一步，因此强调了活化后立即功能化的实际重要性。随着时间的推移，电子特性和润湿性趋于恢复。SIMS 深度分析清楚地说明了老化石墨烯表面的表面成分变化，其低于 XPS 灵敏度。由于等离子体处理通常用作碳材料表面性能调整的第一步，因此强调了活化后立即功能化的实际重要性。随着时间的推移，电子特性和润湿性趋于恢复。SIMS 深度分析清楚地说明了老化石墨烯表面的表面成分变化，其低于 XPS 灵敏度。由于等离子体处理通常用作碳材料表面性能调整的第一步，因此强调了活化后立即功能化的实际重要性。