A facile preparation route for netlike microstructures on a stainless steel using an
ethanol-mediated femtosecond laser irradiation
Hao Bian, Qing Yang, Hewei Liu, Feng Chen
⁎
, Guangqing Du, Jinhai Si, Xun Hou
State Key Laboratory for Manufacturing Systems Engineering & Key Laboratory of Photonics Technology for Information, School of Electronics & Information Engineering, Xi'an Jiaotong
University, Xianing-xilu 28, Xi'an 710049, China
abstractarticle info
Article history:
Received 31 July 2012
Received in revised form 25 September 2012
Accepted 26 October 2012
Available online 2 November 2012
Keywords:
Femtosecond laser
Microstructures
Self-assembly
Surface modification
Netlike or porous microstructures are highly desirable in metal implants and biomedical monitoring applica-
tions. However, realization of such microstructures remains technically challenging. Here, we report a facile
and environmentally friendly method to prepare netlike microstructures on a stainless steel by taking the full ad-
vantage of the liquid-mediated femtosecond laser ablation. An unordered netlike structure and a quasi-ordered
array of holes can be fabricated on the surface of stainless steel via an ethanol-mediated femtosecond laser
line-scan method. SEM analysis of the surface morphology indicates that the porous netlike structure is in the
micrometer scale and the diameter of the quasi-ordered holes ranges from 280 nm to 320 nm. Besides, we
find that the obtained structures are tunable by altering the laser processing parameters especially scanning
speed.
© 2012 Elsevier B.V. All rights reserved.
1. Introduction
Netlike or porous structures on metals with spatial resolutions in
the submicrometer or nanometer scale have received significant at-
tention in material fields over the past decades because of their
unique properties associated with potential applications in biomedi-
cal monitoring, metal implants, optical devices and superhydrophobic
materials [1–4]. Thus, many groups concentrated on the fabrication of
porous nanostructures in the past decades. Reviewing previous
works, approaches to prepare such structures mainly include anodic
oxidation [5], chemical treatment [6], ion beam etching and plasma-
spray [7,8]. Up to now, it still evokes considerable research interest
to develop an efficient and environmentally benign method to pre-
pare porous and netlike structures. And these structures have a
broad prospect of applications in biomedical devices, especially for
those surface-modified metallic implants [9,10].
Therefore, developing a simple and effective fabrication technique
for nano-texturing of metals is a vigorous scientific research field re-
cently. Because of its advantages as a single-step and environmentally
benign process, laser-induced periodic surface structures (LIPSS)
open up an attractive approach for surface-texturing of metals. Since
the 1960s, almost at the time when lasers came out, the periodic micro-
grooves or so-called classic ripples were found after the laser irradiated
the solid surfaces. However, the feature size of these classic ripples is in
the micrometer scale, which cannot satisfy the demands of nanoscale
fabrication.
In recent years, femtosecond laser is successfully established to be
an excellent tool to produce fine nanostructures on various solid mate-
rials, such as metals, dielectrics, semiconductors and polymers. The fea-
ture size of the femtosecond laser-induced periodic surface structures
(FLIPSS) can be reduced to less than 100 nm. Nevertheless, typical fem-
tosecond laser-induced structures reported in the literature had a few
limitations such as nanospikes, random roughness, subwavelength rip-
ple microprotrusions and holes [11–17].
Random nanostructures, like spikes or particles, are usually obtained
at low fluence or single-shot irradiations. Ripples or grating pattern is the
most common FLIPSS which is produced at intermediate fluences. In a
normal case, the interspacing of the ripples (Λ) follows the equation:
Λ ¼ λ=n; ð1Þ
where λ is the laser wavelength and n is the refractive index of the ma-
terials, and the orientation is perpendicular to the laser polarization. For
high-fluence irradiation, the surface structures are produced in the
micrometer scale, such as microprotrusions and holes. The formation of
the aforementioned surface structures involves various processes includ-
ing the inference, surface plasma waves (SPW), self-organization, melting
and resolidification and capillary waves, but which of these processes
dominates the formation mechanism is still an open question. Although
the morphology, mechanisms and applications of the metallic FLIPSS
were widely studied in the past, we notice that most experiments concen-
trated on the FLIPSS of metals produced in air. Herein, we perform our
studies on the metallic FLIPSS produced in ethanol, and interestingly,
some novel surface structures are observed. These types of structures
will increase the surface area of materials and have good applications in
numerous scientific fields.
Materials Science and Engineering C 33 (2013) 663–667
⁎ Corresponding author. Tel./fax: +86 29 82668420.
E-mail address: chenfeng@mail.xjtu.edu.cn (F. Chen).
0928-4931/$ – see front matter © 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.msec.2012.10.014
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