Wettability interpretation of oxygen plasma modified poly(methyl methacrylate)
Wettability interpretation of oxygen plasma modified poly(methyl methacrylate)
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DOI：
10.1021/la048947s
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发表时间：
2004-12-07
期刊：
影响因子：
3.9
通讯作者：
Kwok, DY
中科院分区：
文献类型：
--
作者：
Chai, JN;Lu, FZ;Kwok, DY
用直流脉冲氧气等离子体对聚甲基丙烯酸甲酯(PMMA)进行了不同处理时间的改性。用X射线光电子能谱(XPS)、光学轮廓仪、Zeta电位和提前接触角测量对改性后的表面进行了表征。测得的水推进接触角随流量的变化而显著减小。几种含氧官能团(羰基、羧基、碳酸盐等)XPS检测到，而Zeta电位测量证实处理后的PMMA表面负电荷增加。评价了极性化学物种的浓度与Zeta电位之间的相关性，我们发现表面亲水性的增加是由于引入了氧官能团和产生了电荷态的共同作用。通过在Young‘s方程中引入附加的表面张力项，在接触角的解释中也考虑了双电层效应。我们还发现，EDL对固-液界面张力的贡献可以忽略不计，对于所考虑的体系，可以安全地忽略。
Poly(methyl methacrylate) (PMMA) has been modified via a dc pulsed oxygen plasma for different treatment times. The modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS), optical profilometer, zeta potential, and advancing contact angle measurements. The measured advancing contact angles of water decreased considerably as a function of discharge. Several oxygen-based functionalities (carbonyl, carboxyl, carbonate, etc.) were detected by XPS, while zeta potential measurements confirmed an increase in negative charge for the treated PMMA surface. Evaluating the correlation between the concentration of polar chemical species and zeta potential, we found that increase in surface hydrophilicity results from the coeffect due to incorporation of oxygen functional groups and creation of charge states. The electrical double layer (EDL) effect was also considered in contact angle interpretation by introducing an additional surface tension term into Young's equation. We also found that EDL contribution to the solid-liquid interfacial tension is negligible and can be safely ignored for the systems considered here.