Extreme hydrophobicity and omniphilicity of high-aspect-ratio silicon structures

Citation data:

Modern Physics Letters B, ISSN: 0217-9849, Vol: 29, Issue: 06n07

Publication Year:
2015
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Repository URL:
http://scholarworks.unist.ac.kr/handle/201301/17424
DOI:
10.1142/s0217984915400096
Author(s):
Kwak, Moon Kyu; Park, Cheol Woo; Hwang, Kwang-Il; Park, Choon Man; Jeong, Hoon Eui; Choi, Jun Ho
Publisher(s):
World Scientific Pub Co Pte Lt; WORLD SCIENTIFIC PUBL CO PTE LTD
Tags:
Physics and Astronomy; Black silicon; selective wetting; purification; superhydrophobic surface; environmental remediation
article description
We present an application of high-aspect-ratio (high-AR) silicon structures (black silicon) with high water repellency and good wettability by oils and solvents. The fabrication of black silicon consists of a deep reactive-ion etching process for extremely-high-AR silicon structures and surface treatment with C4F8 gas. Such high-AR structures were found to be highly resistant against wetting by water, but they also have good wetting characteristics with respect to certain liquids such as ethanol, hexane and mineral oil. To determine the relationship between the AR of nanostructures and wetting selectivity, four different black silicon samples with different pattern heights were used. The static contact angles of various liquid were measured for the analysis of wetting properties of the four black silicon samples. To explore feasible applications, ethanol-water separation was performed as a miniaturized experimental simulation of environmental remediation.