Fabrication of Paper-Based Microfluidic Devices Using PECVD for Selective Separation

The interest in microfluidic devices is increasing day by day due to consuming much lower amount of chemicals. Paper-based microfluid device is one of the most important types of microfluidic device, due to the inherent superior properties of papers. This study set out to develop a novel approach to fabricate a pH-responsive paper-based microfluidic device using plasma enhanced chemical vapor deposition (PECVD). Magnets were used for masking the paper surface. Poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) thin film having ionizable groups was coated on the inner surfaces of the microfluidic channel. Hydrophobic poly (2,2,3,4,4,4-hexafluoro butyl acrylate) (PHFBA) thin film was used to produce the barrier of the microchannel. A standard chromatography paper was successfully transformed into pH-responsive paper-based microfluidic device. Due to its inherent vapor-based nature, PECVD method provided excellent conformal coverage on the paper surface without disrupting the surface structures. The selective separation ability of the microfluidic device was tested at different pH values using anionic and cationic analytes. The microfluidic device demonstrated selective separation ability of analytes depending on the pH value of the medium. The obtained results showed that the differences between the retentions of both analytes on the microfluidic device at different pH values are much more than those of the uncoated papers under the same conditions.