Tribological properties of asperity arrays coated with self-assembled monolayers
Tribological properties of asperity arrays coated with self-assembled monolayers
复制标题
自组装单层涂层粗糙体阵列的摩擦学特性
DOI：
10.1007/s11249-007-9197-x
复制
发表时间：
2007
影响因子：
3.2
通讯作者：
S. Mori
中科院分区：
文献类型：
--
作者：
Y. Ando;Yosuke Inoue;K. Kakuta;T. Igari;S. Mori
采用二维微凸体阵列技术研究了自组装单层膜（SAM）对摩擦力和拉脱力的影响。用由五种不同烷基氯硅烷之一组成的SAM涂覆阵列。首先，通过使用聚焦离子束（FIB）系统在硅板上铣削图案来创建二维粗糙阵列。每个硅板具有不同图案的等间距的凹凸体。每个图案（5 × 5 μm2）具有不同的粗糙峰曲率半径，范围约为200至2500 nm。然后，将每个硅板浸入不同的烷基氯硅烷在己烷中的溶液（己基三氯硅烷、辛基三氯硅烷、十二烷基三氯硅烷、十四烷基三氯硅烷或十八烷基三氯硅烷）中，从而用SAM涂覆粗糙阵列。通过使用具有方形平坦探针的原子力显微镜（AFM）测量SAM涂覆的阵列上的摩擦力和拉脱力。SAM涂覆的硅的拉脱力大致与粗糙峰的曲率半径成比例。拉脱力的大小近似对应于通过使用水在SAM表面上的接触角计算的毛细管力。摩擦系数与SAM的烷基链长度的倒数相关。
The effects of a self-assembled monolayer (SAM) coating on the friction and pull-off forces were determined by using two-dimensional asperity arrays on silicon wafers. The arrays were coated with SAM composed of one of five different alkylchlorsilanes. First, two-dimensional asperity arrays were created by using a focussed ion beam (FIB) system to mill patterns on silicon plates. Each silicon plate had different patterns of equally spaced asperities. Each pattern (5 × 5 μm2) had a different radius of curvature of the asperity peaks, ranging from about 200 to 2500 nm. Then, each silicon plate was immersed in a solution of a different alkylchlorsilane in hexane (either hexyltrichlorosilane, octyltrichlorosilane, dodecyltrichlorosilane, tetradecyltrichlorosilane, or octadecyltrichlorosilane), thus coating the asperity arrays with SAM. The friction and pull-off forces on the SAM-coated arrays were measured by using an atomic force microscope (AFM) that had a square flat probe. The pull-off force for SAM-coated silicon was roughly proportional to the radius of curvature of the asperity peaks. The magnitude of the pull-off force corresponded approximately to the capillary force calculated by using the contact angle of water on the surface of SAM. The friction coefficient correlated with the inverse of the alkyl-chain length of the SAM.