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Fabrication of Paper-Based Microfluidic Devices Using PECVD for Selective Separation
Mehmet Gürsoy 한국고분자학회 2021 Macromolecular Research Vol.29 No.6
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 pHresponsive 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.
Gürsoy Mehmet,Çıtak Emre,Karaman Mustafa 한국탄소학회 2022 Carbon Letters Vol.32 No.3
Large-area graphene of the order of centimeters was deposited on copper substrates by low-pressure chemical vapor deposition (LPCVD) using hexane as the carbon source. The effect of temperature and the carrier gas flowrates on the quality and uniformity of the as-deposited graphene was investigated using the Raman analysis. The film deposited at 870 °C with a total carrier gas flowrate of 50 sccm is predominantly single-layer with very low defects according to the Raman spectra. The 2D/G peak intensity ratios obtained from the Raman spectra of samples from three different locations of graphene deposited on a whole copper catalyst was used to calculate the large-area uniformity. Based on the results, a very high uniformity of 89.6% was calculated for the graphene deposited at 870 °C. The uniformity was observed to decrease with increasing temperature. Similar to the thickness uniformity, the electrical conductivity values obtained as a result of I–V measurements and water contact angle measurements were found to be close to each other for the graphene deposited under the same deposition conditions.
Mehmet Gürsoy,Berkan Kocadayıoğulları 한국섬유공학회 2023 Fibers and polymers Vol.24 No.10
Fog harvesting from the air is one of the sustainable and effective methods to obtain fresh water. Energy-free fog collector systems are widely used for this purpose, but the efficiency of traditional meshes used in these systems is not sufficient. The main objective of this study is to transform ordinary polypropylene fabrics into effective fog harvesting materials by coating them with polymeric thin films using plasma-enhanced chemical vapor deposition (PECVD), which is a one-step and environmentally friendly method. Poly(acrylic acid) (PAA) and poly(2,3,4,4,4-hexafluorobutyl acrylate) (PHFBA) thin films were synthesized using PECVD method as hydrophilic and hydrophobic polymers, respectively. In this study, the effects of surface wettability and fabric weight on fog harvesting efficiency were investigated. Moreover, the effect of surface roughness on fog harvesting efficiency was studied by modifying of the fabrics with silica particles before PECVD coating. The fabrics obtained with hydrophobic thin-film coating on roughened surface showed the highest fog harvesting efficiency (1.14 L/m2.h). The results of this study show that the fabrics modified by the method developed here can be a promising alternative to the meshes currently used in fog collector.