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Rendering SU-8 hydrophilic to facilitate use in micro channel fabrication

Tenje, Maria LU ; Rodolphe, Marie; Calleja, Montserrat and Boisen, Anja (2004) In Journal of Micromechanics and Microengineering 14(12). p.1614-1617
Abstract
A simple method is presented to reduce the contact angle of the photo-resist SU-8. A low contact angle is valuable in micro total analysis systems for the fabrication of micro channels where the capillary pressure is linearly related to the cosine of the contact angle, θ. If the surface of the channel is hydrophilic, the capillary pressure can be used as the only means to direct the liquid through the channels and the need for external pumps can be avoided. This is very useful, especially in the fabrication of devices for 'lab-on-a-chip' where it is important to keep the design as simple as possible. A commonly used technique for releasing structures fabricated on Si wafers is to use a sacrificial Cr layer. It is shown that the contact... (More)
A simple method is presented to reduce the contact angle of the photo-resist SU-8. A low contact angle is valuable in micro total analysis systems for the fabrication of micro channels where the capillary pressure is linearly related to the cosine of the contact angle, θ. If the surface of the channel is hydrophilic, the capillary pressure can be used as the only means to direct the liquid through the channels and the need for external pumps can be avoided. This is very useful, especially in the fabrication of devices for 'lab-on-a-chip' where it is important to keep the design as simple as possible. A commonly used technique for releasing structures fabricated on Si wafers is to use a sacrificial Cr layer. It is shown that the contact angle of SU-8 decreases by 40° after etching this layer. A further reduction in contact angle is desirable and can be achieved by treating the sample with ethanolamine at 50 °C for only 10 min. The resulting contact angle is 23° ± 7°. Using a wet chemical treatment, a selective change in contact angle between different areas of a micro channel system can be achieved, without the need to involve different materials in the fabrication process. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Micromechanics and Microengineering
volume
14
issue
12
pages
1614 - 1617
publisher
IOP Publishing
external identifiers
  • scopus:10844258258
ISSN
0960-1317
DOI
10.1088/0960-1317/14/12/003
language
English
LU publication?
no
id
c4ba869a-c044-4199-a9ed-b7a82cd63285 (old id 3157998)
date added to LUP
2012-10-25 17:20:29
date last changed
2017-01-01 07:06:49
@article{c4ba869a-c044-4199-a9ed-b7a82cd63285,
  abstract     = {A simple method is presented to reduce the contact angle of the photo-resist SU-8. A low contact angle is valuable in micro total analysis systems for the fabrication of micro channels where the capillary pressure is linearly related to the cosine of the contact angle, θ. If the surface of the channel is hydrophilic, the capillary pressure can be used as the only means to direct the liquid through the channels and the need for external pumps can be avoided. This is very useful, especially in the fabrication of devices for 'lab-on-a-chip' where it is important to keep the design as simple as possible. A commonly used technique for releasing structures fabricated on Si wafers is to use a sacrificial Cr layer. It is shown that the contact angle of SU-8 decreases by 40° after etching this layer. A further reduction in contact angle is desirable and can be achieved by treating the sample with ethanolamine at 50 °C for only 10 min. The resulting contact angle is 23° ± 7°. Using a wet chemical treatment, a selective change in contact angle between different areas of a micro channel system can be achieved, without the need to involve different materials in the fabrication process.},
  author       = {Tenje, Maria and Rodolphe, Marie and Calleja, Montserrat and Boisen, Anja},
  issn         = {0960-1317},
  language     = {eng},
  number       = {12},
  pages        = {1614--1617},
  publisher    = {IOP Publishing},
  series       = {Journal of Micromechanics and Microengineering},
  title        = {Rendering SU-8 hydrophilic to facilitate use in micro channel fabrication},
  url          = {http://dx.doi.org/10.1088/0960-1317/14/12/003},
  volume       = {14},
  year         = {2004},
}