Fabrication of "roll-off" and "sticky" superhydrophobic cellulose surfaces via plasma processing
Fabrication of "roll-off" and "sticky" superhydrophobic cellulose surfaces via plasma processing
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DOI：
10.1021/la703766c
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发表时间：
2008-05-06
期刊：
影响因子：
3.9
通讯作者：
Hess, Dennis W.
中科院分区：
文献类型：
--
作者：
Balu, Balarnurali;Breedveld, Victor;Hess, Dennis W.
迄今为止，大多数人造超疏水表面都是不可生物降解的，不可再生的，也不具有机械柔性，并且通常价格昂贵，这限制了它们的潜在应用。相比之下，纤维素是一种可生物降解、可再生、柔性、廉价的生物聚合物，在自然界中大量存在，满足所有上述要求，但它不是超疏水性的。纤维素纸上的超疏水性，获得通过域选择性蚀刻的无定形部分的纤维素在氧等离子体中，随后涂层的蚀刻表面与通过等离子体增强的化学气相沉积，使用五氟乙烷作为前体沉积的薄氟碳膜。等离子体处理的变化产生两种类型的超疏水性：“滚降”（接触角（CA），166.7度+/-0.9度; CA滞后，3.4度+/-0.1度）和接近超疏水性的“粘性”（CA，144.8度+/-5.7度; CA滞后，79.1度+/-15.8度）。当与通过传统聚合物接枝、纳米颗粒沉积或其他人工手段产生的粗糙化结构相比时，通过描绘每个纤维的内部粗糙度获得的纳米级粗糙度和纤维素纸表面固有的微米级粗糙度是稳健的。
Most of the artificial superhydrophobic surfaces that have been fabricated to date are not biodegradable, renewable, or mechanically flexible and are often expensive, which limits their potential applications. In contrast, cellulose, a biodegradable, renewable, flexible, inexpensive, biopolymer which is abundantly present in nature, satisfies all the above requirements, but it is not superhydrophobic. Superhydrophobicity on cellulose paper was obtained by domain-selective etching of amorphous portions of the cellulose in an oxygen plasma and subsequently coating the etched surface with a thin fluorocarbon film deposited via plasma-enhanced chemical vapor deposition using pentafluoroethane as a precursor. Variation of plasma treatment yielded two types of superhydrophobicity : "roll-off' (contact angle (CA), 166.7 degrees +/- 0.9 degrees; CA hysteresis, 3.4 degrees +/- 0.1 degrees) and "sticky" (CA, 144.8 degrees +/- 5.7 degrees; CA hysteresis, 79.1 degrees +/- 15.8 degrees) near superhydrophobicity. The nanometer scale roughness obtained by delineating the internal roughness of each fiber and the micrometer scale roughness which is inherent to a cellulose paper surface are robust when compared to roughened structures created by traditional polymer grafting, nanoparticle deposition, or other artificial means.