Lin Meng-Hsien, Chen Chi-Fan, Shiu Hung-Wei, Chen Chia-Hao, Gwo Shangjr
Institute of Nanoengineering and Microsystems, Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan.
J Am Chem Soc. 2009 Aug 12;131(31):10984-91. doi: 10.1021/ja901619h.
We present a generic and efficient chemical patterning method based on local plasma-induced conversion of surface functional groups on self-assembled monolayers (SAMs). Here, spatially controlled plasma exposure is realized by elastomeric poly(dimethylsiloxane) (PDMS) contact masks or channel stamps with feature sizes ranging from nanometer, micrometer, to centimeter. This chemical conversion method has been comprehensively characterized by a set of techniques, including contact angle measurements, X-ray photoelectron spectroscopy (XPS), scanning photoelectron microscopy (SPEM), scanning electron microscopy (SEM), and scanning Kelvin probe microscopy (SKPM). In particular, XPS and SPEM can be used to distinguish regions of different surface functionalities and elucidate the mechanism of plasma-induced chemical conversion. In the case of an octadecyltrichlorosilane (OTS) monolayer, we show that exposure to low-power air plasma causes hydroxylation and oxidation of the methyl terminal group on an OTS-covered Si surface and generates polar functional groups such as hydroxyl, aldehylde, and carboxyl groups, which can allow subsequent grafting of dissimilar SAMs and adsorption of colloid nanoparticles onto the patterned areas with an achievable resolution down to the 50 nm range.
我们提出了一种基于局部等离子体诱导自组装单分子层（SAMs）表面官能团转化的通用且高效的化学图案化方法。在此，通过弹性体聚二甲基硅氧烷（PDMS）接触掩膜或特征尺寸范围从纳米、微米到厘米的通道印章实现空间控制的等离子体暴露。这种化学转化方法已通过一系列技术进行了全面表征，包括接触角测量、X射线光电子能谱（XPS）、扫描光电子显微镜（SPEM）、扫描电子显微镜（SEM）和扫描开尔文探针显微镜（SKPM）。特别是，XPS和SPEM可用于区分不同表面官能团的区域，并阐明等离子体诱导化学转化的机制。在十八烷基三氯硅烷（OTS）单分子层的情况下，我们表明，暴露于低功率空气等离子体中会导致OTS覆盖的Si表面上甲基端基发生羟基化和氧化，并生成极性官能团，如羟基、醛基和羧基，这可以允许后续在图案化区域接枝不同的SAMs并吸附胶体纳米颗粒，可实现低至50 nm范围的分辨率。
