Maheshwari, Nidhi and Kottantharayil, Anil and Kumar, Mahesh and Mukherji, Soumyo (2010) Long term hydrophilic coating on poly(dimethylsiloxane) substrates for microfluidic applications. Applied Surface Science, 257 (2). pp. 451-457. ISSN 0169-4332

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Poly(dimethylsiloxane) (PDMS) has been used extensively for microfluidic components and as substrates for biological applications. Since the native nature of PDMS is hydrophobic it requires a functionalization step for use in conjunction with aqueous media. Commonly, oxygen plasma treatment is used for the formation of hydrophilic groups on the surface. However, the hydrophilic nature of these surfaces is short lived and the surfaces quickly revert back to their original hydrophobic state. In this work, branched-polyethylenimine (b-PEI) was used for long term modification of plasma treated PDMS surface. Contact angle, X-ray photoelectron spectroscopy (XPS) and Atomic force microscopy (AFM) were used for characterization of the modified surfaces and their stability with time was studied. The results obtained demonstrate that comparatively higher stability, hydrophilic, positively charged surfaces can be obtained after b-PEI treatment. These b-PEI treated PDMS surfaces can be used as fluidic channels for the separation of molecules as well as a substrate for the adherence of bio-molecules or biological cells.

Item Type: Article
Additional Information: Copyright for this article belongs to M/s Elsevier B.V.
Uncontrolled Keywords: Poly(dimethylsiloxane) (PDMS); Plasma oxidation; Polyethylenimine (PEI); XPS; Surface modification; Contact angle
Subjects: Chemistry
Materials Science
Depositing User: Ms Neetu Chandra
Date Deposited: 24 May 2012 08:09
Last Modified: 24 May 2012 08:09

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