氧化铝表面全氟烷基异氰酸酯单分子层的疏水性

Hydrophobicity of perfluoroalkyl isocyanate monolayers on oxidized aluminum surfaces.

作者信息

Hozumi Atsushi, Kim Bokyung, McCarthy Thomas J

机构信息

National Institute of Advanced Industrial Science & Technology (AIST) Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan.

出版信息

Langmuir. 2009 Jun 16;25(12):6834-40. doi: 10.1021/la804127z.

DOI:10.1021/la804127z

PMID:19432482

Abstract

Perfluoroalkyl isocyanate-derived monolayers were prepared on oxidized aluminum surfaces by chemical vapor deposition (CVD) of 1H,1H,2H,2H-perfluorodecyl isocyanate (CF(3)CF(2)CH(2)CH(2)N horizontal lineC horizontal lineO, i.e., R(F)-NCO). Two types of oxidized aluminum substrates were studied: electrochemically polished aluminum plates (Al(Al(2))(O(3))) and Al(Al(2))(O(3)) that was treated with boiling water ((BW)Al(Al(2))(O(3))). X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) confirmed that this CVD method produces a monolayer with a thickness of approximately 1.2 nm on Al(Al(2))(O(3)) through a carbamate linkage without discernible change in surface morphology. After monolayer deposition, hydrophilic Al(Al(2))(O(3)) surfaces become hydrophobic. Advancing and receding water contact angles are theta(A)/theta(R) = 125 degrees /103 degrees . AFM indicates that (BW)Al(Al(2))(O(3)) surfaces contain 10-15-nm-size pebble-like features. This is due to both chemical and physical erosion of the aluminum surface caused by the boiling water treatment. Due to the presence of these topographical features, the CVD of R(F)-NCO on (BW)Al(Al(2))(O(3)) induces superhydrophobicity (theta(A)/theta(R) = 167 degrees /165 degrees ). Al(Al(2))(O(3)) and (BW)Al(Al(2))(O(3)) based "control surfaces" were prepared with the conventional mono- and trifunctional organosilanes, 1H,1H,2H,2H-perfluorodecyldimethylchlorosilane (CF(3)CF(2)CH(2)CH(2)SiCH(3)Cl, R(F)-SiMe(2)Cl) and 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CF(3)CF(2)CH(2)CH(2)SiOCH(3), R(F)-SiOMe) for comparison. In the case of R(F)-Si(OMe)(3), the theta(A)/theta(R) values for Al(Al(2))(O(3)) and (BW)Al(Al(2))(O(3)) are 125 degrees /110 degrees and 170 degrees /167 degrees , respectively. R(F)-SiMe(2)Cl-treated aluminum surfaces are much less hydrophobic. The theta(A)/theta(R) values for Al(Al(2))(O(3)) and (BW)Al(Al(2))(O(3)) are 107 degrees /69 degrees and 137 degrees /87 degrees , respectively. XPS analysis of surface coverage is consistent with the contact angle behavior and the water sensitivity. Stability of these three monolayers in water is in the order: R(F)-Si(OMe)(3) > R(F)-NCO >> R(F)-SiMe(2)Cl.

摘要

通过1H,1H,2H,2H-全氟癸基异氰酸酯（CF(3)CF(2)CH(2)CH(2)N═C═O，即R(F)-NCO）的化学气相沉积（CVD）法，在氧化铝表面制备了全氟烷基异氰酸酯衍生的单分子层。研究了两种类型的氧化铝基底：电化学抛光铝板（Al(Al(2))(O(3))）和经沸水处理的Al(Al(2))(O(3))（(BW)Al(Al(2))(O(3))）。X射线光电子能谱（XPS）和原子力显微镜（AFM）证实，这种CVD方法通过氨基甲酸酯键在Al(Al(2))(O(3))上生成了厚度约为1.2 nm的单分子层，且表面形态无明显变化。单分子层沉积后，亲水性的Al(Al(2))(O(3))表面变得疏水。前进和后退水接触角为θ(A)/θ(R)=125°/103°。AFM表明，(BW)Al(Al(2))(O(3))表面含有10 - 15 nm大小的卵石状特征。这是由于沸水处理对铝表面造成的化学和物理侵蚀。由于这些形貌特征的存在，R(F)-NCO在(BW)Al(Al(2))(O(3))上的CVD诱导产生超疏水性（θ(A)/θ(R)=167°/165°）。基于Al(Al(2))(O(3))和(BW)Al(Al(2))(O(3))的“对照表面”采用传统的单官能和三官能有机硅烷1H,1H,2H,2H-全氟癸基二甲基氯硅烷（CF(3)CF(2)CH(2)CH(2)SiCH(3)Cl，R(F)-SiMe(2)Cl）和1H,1H,2H,2H-全氟癸基三甲氧基硅烷（CF(3)CF(2)CH(2)CH(2)SiOCH(3)，R(F)-SiOMe）制备，用于比较。对于R(F)-SiOMe，Al(Al(2))(O(3))和(BW)Al(Al(2))(O(3))的θ(A)/θ(R)值分别为125°/110°和170°/167°。R(F)-SiMe(2)Cl处理的铝表面疏水性要低得多。Al(Al(2))(O(3))和(BW)Al(Al(2))(O(3))的θ(A)/θ(R)值分别为107°/69°和137°/87°。表面覆盖度的XPS分析与接触角行为和水敏感性一致。这三种单分子层在水中的稳定性顺序为：R(F)-SiOMe>R(F)-NCO>>R(F)-SiMe(2)Cl。