TY - JOUR
T1 - Self-assembly of nanowires at three-phase contact lines on superhydrophobic surfaces
AU - Tsai, Yao Tsan
AU - Xu, Wei
AU - Yang, Eui Hyeok
AU - Choi, Chang Hwan
PY - 2010/6
Y1 - 2010/6
N2 - This paper reports on a novel self-assembly method of nanowires using a superhydrophobic surface as a template. Well-defined superhydrophobic structures on a template surface can configure three-phase (liquid-solid-gas) contact lines at the structures' tips and direct the site-specific self-assembly of nanowires when the colloidal droplet of nanowires recedes in evaporation. Highaspect- ratio microstructures with tapered tips were fabricated by deep reactive ion etching (DRIE) and coated with a thin layer of Teflon for hydrophobicity. Nickel nanowires were synthesized by electrodeposition through a porous alumina membrane. A uniformly dispersed nanowire suspension was dispensed and evaporated on the superhydrophobic template surface at normal room conditions. After complete evaporation, the assembly of nanowires on the tip structures was measured by microscopy. The results show that nanowires are mostly deposited on the structural tips because the air layer retained between the hydrophobic surface structures prevent the liquid meniscus from reaching to the bottom trenches during evaporation. The assembly rate on each tip and the alignment tendency along the surface pattern vary depending on the template surface parameters and the nanowires colloidal states, requiring further systematic studies on the effects. It is envisioned that well-tailored superhydrophobic surfaces can serve as a novel template for highly-ordered and site-specific self-assembly of functional nanomaterials in simple drying processes, significantly enhancing the capability to realize future nanomaterial-based devices and systems.
AB - This paper reports on a novel self-assembly method of nanowires using a superhydrophobic surface as a template. Well-defined superhydrophobic structures on a template surface can configure three-phase (liquid-solid-gas) contact lines at the structures' tips and direct the site-specific self-assembly of nanowires when the colloidal droplet of nanowires recedes in evaporation. Highaspect- ratio microstructures with tapered tips were fabricated by deep reactive ion etching (DRIE) and coated with a thin layer of Teflon for hydrophobicity. Nickel nanowires were synthesized by electrodeposition through a porous alumina membrane. A uniformly dispersed nanowire suspension was dispensed and evaporated on the superhydrophobic template surface at normal room conditions. After complete evaporation, the assembly of nanowires on the tip structures was measured by microscopy. The results show that nanowires are mostly deposited on the structural tips because the air layer retained between the hydrophobic surface structures prevent the liquid meniscus from reaching to the bottom trenches during evaporation. The assembly rate on each tip and the alignment tendency along the surface pattern vary depending on the template surface parameters and the nanowires colloidal states, requiring further systematic studies on the effects. It is envisioned that well-tailored superhydrophobic surfaces can serve as a novel template for highly-ordered and site-specific self-assembly of functional nanomaterials in simple drying processes, significantly enhancing the capability to realize future nanomaterial-based devices and systems.
KW - Evaporation
KW - Nanowires
KW - Self-Assembly
KW - Superhydrophobic.
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U2 - 10.1166/nnl.2010.1073
DO - 10.1166/nnl.2010.1073
M3 - Article
AN - SCOPUS:79951863425
SN - 1941-4900
VL - 2
SP - 150
EP - 156
JO - Nanoscience and Nanotechnology Letters
JF - Nanoscience and Nanotechnology Letters
IS - 2
ER -