Rapid Transformation in Wetting Properties of PTFE Membrane Using Plasma Treatment

Abstract

In this paper, we describe the surface modification of polytetrafluoroethylene (PTFE) through the plasma treatment process. Several parameters including different active gases, RF power, distance between the plasma source and sample, and plasma duration were optimized to reduce the hydrophobic nature of PTFE. Three different active gases were used (i.e., N2, O2, and (Ar+H2)); N2 was effective to reduce the hydrophobicity of PTFE within a shorter plasma duration of 2 min. Several surface characterizations including ATR-FTIR, water contact angle, FE-SEM, and XPS were utilized to verify the neat and modified PTFE surface after plasma treatment. The plasma treatment using N2 as an active gas improved the wettability of the PTFE membrane, showing a water contact angle of 109.5° when compared with the neat PTFE (141.9°). The SEM images of plasma-treated PTFE showed greater modifications on the surface indicating non-uniform fiber alignment and torn fibers at several places. The obtained results confirm the fact that plasma treatment is an effective way to modify the PTFE surface without altering its bulk property.

Enhanced Wettability and Adhesive Property of PTFE through Surface Modification with Fluorinated Compounds

“…The key takeaway is that a relatively short N 2 plasma treatment (20 s) effectively alters the surface properties of both PFOA-and PFOL-coated PTFE, transforming them from highly hydrophobic (θ = 142 • ) to moderately hydrophilic (θ ≈ 80 • ) (comparable to He/AA plasma treatment showing 67.8 • for PTFE) [18]. This shift aligns with previous research [23] suggesting that N 2 plasma treatment can effectively render PTFE surfaces more water interactive. The underlying mechanism involves the combined effects of the fluoro-compound coatings, introducing hydrophilic groups like -COOH and -OH and the N 2 plasma, which promotes defluorination and hydrogen absorption on the surface [7,8].…”

“…For the plasma treatment, the dried PTFE sheet was positioned on the sample holder of the plasma equipment, ensuring secure placement. Based on prior research [23], it was established that using nitrogen (N 2 ) as the active gas with a 2-min plasma exposure effectively produced a hydrophilic surface. Accordingly, the procedure was replicated here, with specific flow rates set at 4.5 L/min for the carrier gas (argon) and 20 mL/min for the active gas (nitrogen), with an RF power of 150 W and maintaining the distance between the plasma nozzle and Teflon sheet to 3 mm.…”

“…In essence, plasma treatment offers a powerful and versatile approach to surface modification. Its ability to precisely control surface properties while maintaining the bulk integrity of the material makes it a valuable tool across various industries [19][20][21][22][23][24].…”

“…In previous reports, the authors used plasma treatments alone or the hydrophilic compound is passed along with the active gas. Expanding on our previous research [23] on inducing hydrophilicity in PTFE through plasma treatment, this study goes further to enhance the stability of the modified surface. We previously examined various active gases and treatment durations and found that plasma treatment using 'Ar' as carrier gas and 'N 2 ' as active gas for 2 min of plasma duration was most effective in reducing the water contact angle of PTFE from 135 • to 78 • .…”

Study on the Electrical Insulation Properties of Modified PTFE at High Temperatures

“…However, there remain certain deficiencies in the current insulation performance of PTFE in extreme aviation environments. In order to improve the insulation performance of aviation cables, with the exception of adopting insulation materials with better performance, the existing insulation materials are usually modified in various ways [18]. Guo et al observed the influence of the surface roughness of the PTFE material on the luminescence phenomenon and discharge path before surface flashover using enhanced charge-coupled devices.…”