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Patterned microfluidic channels using self-assembled hydroxy-phenyl porphyrin monolayer

DSpace at IIT Bombay

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Title Patterned microfluidic channels using self-assembled hydroxy-phenyl porphyrin monolayer
 
Creator NAYAK, K
KULKARNI, PD
DEEPU, A
SITARAMAN, VR
PUNIDHA, SOUMYA
SAHA, AA
RAVIKANTH, M
MITRA, SK
MUKHERJI, S
RAMGOPAL RAO, V
 
Subject contact angle
flow instability
flow simulation
microchannel flow
microfluidics
monolayers
 
Description In order to achieve patterned surfaces for microfluidic applications, we show for the first time the use of self-assembled monolayer (SAM) of Hydroxy-phenyl porphyrin on SiO2 surface following a chemical procedure. The SAM was characterized using ground state UV-absorption spectroscopy and H2O contact angle measurements. The UV-absorption spectra of the SAM exhibited a ~ 8 nm red shift in the Soret band compared to the porphyrin in toluene. This indicated the side-by-side orientation of the self assembled porphyrin molecules on SiO2. The molecular self-assembly is expected to be randomly oriented because of amorphous nature of the substrate. Sessile deionized (DI) water drop of 50 muL on SAM exhibited a contact angle of 75plusmn3. which is significantly higher than the contact angle of 33plusmn2. measured on the SiO2 substrate. In this paper, we also demonstrate an approach of patterning the SiO2 surface with the porphyrin SAM in order to achieve alternate hydrophobic/hydrophilic surfaces on a p-type device-quality (111) Si wafer. The application of such patterned surfaces is demonstrated with the help of microfluidic simulations study. A three-dimensional numerical simulation of flow in patterned microchannels with alternate layers of hydrophilic and hydrophobic surfaces at the bottom wall is studied here. Volume of fluid method (VOF) is used for simulating the free surface flow in the microchannel. Non-symmetric meniscus profiles with varying amplitude and shapes are obtained by changing the contact angles of the hydrophilic and hydrophobic surfaces. Flow instability is found to increase in the microchannels with patterned surfaces containing a variation in contact angles.
 
Publisher IEEE
 
Date 2009-01-29T12:07:50Z
2011-11-28T07:17:29Z
2011-12-15T09:56:57Z
2009-01-29T12:07:50Z
2011-11-28T07:17:29Z
2011-12-15T09:56:57Z
2007
 
Type Article
 
Identifier Proceedings of the 7th IEEE Conference on Nanotechnology, Hong Kong, 2-5 August 2007, 1235-1239
978-1-4244-0607-4
10.1109/NANO.2007.4601406
http://hdl.handle.net/10054/584
http://dspace.library.iitb.ac.in/xmlui/handle/10054/584
 
Language en