Slaughter Liane S, Cheung Kevin M, Kaappa Sami, Cao Huan H, Yang Qing, Young Thomas D, Serino Andrew C, Malola Sami, Olson Jana M, Link Stephan, Häkkinen Hannu, Andrews Anne M, Weiss Paul S
California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Beilstein J Nanotechnol. 2017 Dec 8;8:2648-2661. doi: 10.3762/bjnano.8.265. eCollection 2017.
The supported monolayer of Au that accompanies alkanethiolate molecules removed by polymer stamps during chemical lift-off lithography is a scarcely studied hybrid material. We show that these Au-alkanethiolate layers on poly(dimethylsiloxane) (PDMS) are transparent, functional, hybrid interfaces that can be patterned over nanometer, micrometer, and millimeter length scales. Unlike other ultrathin Au films and nanoparticles, lifted-off Au-alkanethiolate thin films lack a measurable optical signature. We therefore devised fabrication, characterization, and simulation strategies by which to interrogate the nanoscale structure, chemical functionality, stoichiometry, and spectral signature of the supported Au-thiolate layers. The patterning of these layers laterally encodes their functionality, as demonstrated by a fluorescence-based approach that relies on dye-labeled complementary DNA hybridization. Supported thin Au films can be patterned via features on PDMS stamps (controlled contact), using patterned Au substrates prior to lift-off (e.g., selective wet etching), or by patterning alkanethiols on Au substrates to be reactive in selected regions but not others (controlled reactivity). In all cases, the regions containing Au-alkanethiolate layers have a sub-nanometer apparent height, which was found to be consistent with molecular dynamics simulations that predicted the removal of no more than 1.5 Au atoms per thiol, thus presenting a monolayer-like structure.
在化学剥离光刻过程中，聚合物印章去除链烷硫醇盐分子后所形成的负载金单层是一种研究较少的混合材料。我们表明，聚二甲基硅氧烷（PDMS）上的这些金-链烷硫醇盐层是透明、功能性的混合界面，可在纳米、微米和毫米长度尺度上进行图案化。与其他超薄金膜和纳米颗粒不同，剥离的金-链烷硫醇盐薄膜缺乏可测量的光学特征。因此，我们设计了制造、表征和模拟策略，以探究负载的金硫醇盐层的纳米级结构、化学功能、化学计量和光谱特征。这些层的图案化在横向编码了它们的功能，基于染料标记的互补DNA杂交的荧光方法证明了这一点。负载的薄金膜可以通过PDMS印章上的特征（受控接触）进行图案化，在剥离之前使用图案化的金基板（例如选择性湿法蚀刻），或者通过在金基板上对链烷硫醇进行图案化，使其在选定区域而非其他区域具有反应性（受控反应性）。在所有情况下，含有金-链烷硫醇盐层的区域具有亚纳米级的表观高度，这与分子动力学模拟结果一致，该模拟预测每个硫醇最多去除1.5个金原子，从而呈现出类似单层的结构。
