Drastic Improvement in Adhesion Property of Polytetrafluoroethylene (PTFE) via Heat-Assisted Plasma Treatment Using a Heater

Abstract

The heating effect on the adhesion property of plasma-treated polytetrafluoroethylene (PTFE) was examined. For this purpose, a PTFE sheet was plasma-treated at atmospheric pressure while heating using a halogen heater. When plasma-treated at 8.3 W/cm2 without using the heater (Low-P), the surface temperature of Low-P was about 95 °C. In contrast, when plasma-treated at 8.3 W/cm2 while using the heater (Low-P+Heater), the surface temperature of Low-P+Heater was controlled to about 260 °C. Thermal compression of the plasma-treated PTFE with or without heating and isobutylene−isoprene rubber (IIR) was performed, and the adhesion strength of the IIR/PTFE assembly was measured via the T-peel test. The adhesion strengths of Low-P and Low-P+Heater were 0.12 and 2.3 N/mm, respectively. Cohesion failure of IIR occurred during the T-peel test because of its extremely high adhesion property. The surfaces of the plasma-treated PTFE with or without heating were investigated by the measurements of electron spin resonance, X-ray photoelectron spectroscopy, nanoindentation, scanning electron microscopy, and scanning probe microscopy. These results indicated that heating during plasma treatment promotes the etching of the weak boundary layer (WBL) of PTFE, resulting in a sharp increase in the adhesion property of PTFE.

Influence of air contamination during heat-assisted plasma treatment on adhesion properties of polytetrafluoroethylene (PTFE)

“…It was previously reported that plasma treatment at low temperature (below 100 C) has a little effect on the adhesion property of PTFE and HAP treatment (above 200 C) has a signicant effect on its adhesion property. [20][21][22] Thus, the surface of each PTFE sheet was modied via HAP treatment according to the protocol reported previously. 21 However, in this study, the air concentration was controlled by the base pressure (as shown in ESI-1 †) during the HAP treatment.…”

“…HAP treatment involves applying heat to the PTFE surface by plasma treatment to induce surface hardening and introduce oxygen-containing functional groups. 20,21 HAP treatment has been shown to effectively improve both the indirect adhesion using an adhesive and direct adhesion (without an adhesive) of PTFE to other materials. 22 However, the HAP treatment in the previous studies was a leaf-type process: the pressure in the chamber was reduced to below 10 Pa using a rotary vacuum pump, and helium (He) gas was subsequently owed into the chamber until it reached atmospheric pressure (101 300 Pa).…”

“…20,21 HAP treatment has been shown to effectively improve both the indirect adhesion using an adhesive and direct adhesion (without an adhesive) of PTFE to other materials. 22 However, the HAP treatment in the previous studies was a leaf-type process: the pressure in the chamber was reduced to below 10 Pa using a rotary vacuum pump, and helium (He) gas was subsequently owed into the chamber until it reached atmospheric pressure (101 300 Pa). [20][21][22] Thus, although the HAP treatment was conducted at atmospheric pressure, it was not an open-air-type plasma treatment, which limits the process throughput.…”

“…22 However, the HAP treatment in the previous studies was a leaf-type process: the pressure in the chamber was reduced to below 10 Pa using a rotary vacuum pump, and helium (He) gas was subsequently owed into the chamber until it reached atmospheric pressure (101 300 Pa). [20][21][22] Thus, although the HAP treatment was conducted at atmospheric pressure, it was not an open-air-type plasma treatment, which limits the process throughput. Therefore, the throughput of the HAP treatment is low.…”

Low fractal dimension modified drilling‐hole wall for PTFE high‐frequency board copper plating with plasma treatment

“…However, there is a concern in this method due to serious environmental pollution and thus hurts the human body health . What is more, it may blacken the surface and reduce surface resistance of PTFE in high temperature environment . Therefore, the alternative approach of hole metallization pretreatment over PTFE with improved quality for high‐frequency and environmental‐friendly waste is absolutely desirable.…”