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Asrafali SP, Periyasamy T, Kim SC, Lee JW. Enhanced Wettability and Adhesive Property of PTFE through Surface Modification with Fluorinated Compounds. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3051. [PMID: 38998134 PMCID: PMC11242136 DOI: 10.3390/ma17133051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 06/17/2024] [Accepted: 06/19/2024] [Indexed: 07/14/2024]
Abstract
Polytetrafluoroethylene (PTFE) is prized for its unique properties in electrical applications, but its natural hydrophobicity poses challenges as it repels water and can cause electrical short circuits, shortening equipment lifespan. In this work, the mentioned issue has been tackled by using two different fluorinated compounds, such as perfluorooctanoic acid (PFOA)/perfluorooctanol (PFOL), along with plasma processing to enhance the surface hydrophilicity (water attraction) of PTFE. This method, demonstrated on Teflon membrane, quickly transformed their surfaces from hydrophobic to hydrophilic in less than 30 s. The treated films achieved a water contact angle saturation of around 80°, indicating a significant increase in water affinity. High-resolution C 1s X-ray photoelectron spectroscopy (XPS) confirmed the formation of new bonds, such as -COOH and -OH, on the surface, responsible for enhanced hydrophilicity. Extended plasma treatment led to further structural changes, evidenced by increased intensity in infrared (IR) and Raman spectra, particularly sensitive to vibrations associated with the C-F bond. Moreover, Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR) showed the formation of surface-linked functional groups, which contributed to the improved water attraction. These findings decisively show that treatment with fluoro-compound along with plasma processing can be considered as a highly effective and rapid method for converting PTFE surfaces from hydrophobic to hydrophilic, facilitating its broader use in various electrical applications.
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Affiliation(s)
| | - Thirukumaran Periyasamy
- Department of Fiber System Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Seong-Cheol Kim
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Jae-Woong Lee
- Department of Fiber System Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
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Idrees H, Ali S, Sajid M, Rashid M, Khawaja FI, Ali Z, Anwar MN. Techno-Economic Analysis of Vacuum Membrane Distillation for Seawater Desalination. MEMBRANES 2023; 13:339. [PMID: 36984726 PMCID: PMC10058618 DOI: 10.3390/membranes13030339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Seawater desalination is an affordable and viable solution to the growing freshwater scarcity problem in water scarce regions. The current study focuses on cost analysis of Vacuum Membrane Distillation (VMD) setup for removing salts from water. The membrane used in the flat sheet VMD module was Polytetrafluoroethylene (PTFE) with 250 mm × 200 mm dimensions and 165 µm thickness. The experiments were carried out with variations in parameters such as velocity, pressure, concentration, and temperature. For the cost analysis, the operational, maintenance, instrumentation, and capital cost of the lab model was considered and then upscaled. A range of experiments was performed for NaCl and KCl under variations of operating parameters. It was noted that, for the NaCl solution, the increase in temperature from 50 °C to 70 °C doubled the permeate flux. However, for the conditions tested, the concentration shift from 0.25 M to 0.75 M decreased the permeate flux by 1.4% because the increase in ion concentrations along the membrane lowers the vapor pressure, restricting the permeate flux. The results trend for the KCl solution was similar to the NaCl; at temperature T1, it was noted that increased concentration from 0.25 M to 0.75 M significantly reduces the permeate flow. The reduction in permeate flow was nonlinear for a given pressure 30 kPa and velocity 5.22 m/s, but linear for all other variables. It was also observed that with an increase in temperature from 60 °C to 70 °C, the permeate flux for concentration 0.25 M was 49% for all the combinations of pressure and velocity. In addition, permeate flow increased 53% from temperature 50 °C to 60 °C and 49% from temperature 60 °C to 70 °C for both the solutions at a concentration of 0.25 M. This shows that the temperature also had a profound impact on the permeate flux. The economic analysis and market survey shows that the cost of clean water at the lab level was high which can be significantly reduced using a large-scale setup providing 1,000,000 L/H of distilled water.
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Affiliation(s)
- Hassaan Idrees
- School of Mechanical and Manufacturing Engineering (SMME), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
- Artificial Intelligence for Mechanical Systems (AIMS) Lab, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
| | - Sara Ali
- School of Mechanical and Manufacturing Engineering (SMME), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
- Human Robot Interaction (HRI) Lab, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
- Intelligent Field Robotics Lab (IFRL), National Center for Artificial Intelligence (NCAI), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
| | - Muhammad Sajid
- School of Mechanical and Manufacturing Engineering (SMME), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
- Artificial Intelligence for Mechanical Systems (AIMS) Lab, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
| | - Muhammad Rashid
- Department of Computer Science, National University of Technology (NUTECH), Islamabad 44000, Pakistan
| | - Fahad Iqbal Khawaja
- School of Mechanical and Manufacturing Engineering (SMME), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
- Intelligent Field Robotics Lab (IFRL), National Center for Artificial Intelligence (NCAI), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
| | - Zaib Ali
- School of Mechanical and Manufacturing Engineering (SMME), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
| | - Muhammad Nabeel Anwar
- School of Mechanical and Manufacturing Engineering (SMME), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan
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Kobayashi M, Nishimura F, Kim JH, Yonezawa S. Dyeable Hydrophilic Surface Modification for PTFE Substrates by Surface Fluorination. MEMBRANES 2023; 13:57. [PMID: 36676864 PMCID: PMC9865303 DOI: 10.3390/membranes13010057] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/25/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
Polytetrafluoroethylene (PTFE) is the most widely used fluoropolymer that has various functionalities such as heat resistance, chemical resistance, abrasion resistance, and non-adhesiveness. However, PTFE is difficult to dye because of its high water repellency. In this study, the PTFE surface was modified by a combination of gold sputtering and surface fluorination to improve dyeability. X-ray photoelectron spectroscopy indicated that, compared with the untreated sample, the gold-sputtered and acid-washed surface of PTFE had a negligible number of C-F terminals. Furthermore, the intensity of the C-C peak increased drastically. The polar groups (C=O and C-Fx) increased after surface fluorination, which enhanced the electronegativity of the surface according to the zeta potential results. Dyeing tests with methylene blue basic dye showed that the dye staining intensity on the surface of fluorinated PTFE samples was superior to other samples. It is due to the increased surface roughness and the negatively charged surface of fluorinated PTFE samples. The modified PTFE substrates may find broad applicability for dyeing, hydrophilic membrane filters, and other adsorption needs.
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Affiliation(s)
- Mizuki Kobayashi
- Department of Materials Science and Engineering, Faculty of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
| | - Fumihiro Nishimura
- Cooperative Research Center, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
| | - Jae-Ho Kim
- Department of Materials Science and Engineering, Faculty of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
| | - Susumu Yonezawa
- Cooperative Research Center, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
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