Miyake Erika, Nishino Misa, Seto Yosuke, Komatsu Izuru, Endo Katsuyoshi, Yamamura Kazuya, Ohkubo Yuji
Graduate School of Engineering, Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan
Toshiba Corporate Manufacturing Engineering Center 33 Shin-Isogo-cho, Isogo-ku Yokohama 235-0017 Japan.
RSC Adv. 2023 Jan 9;13(3):1834-1841. doi: 10.1039/d2ra05749b. eCollection 2023 Jan 6.
Polytetrafluoroethylene (PTFE) has high-frequency characteristics and low transmission loss, and is expected to be used as a substrate material of printed wiring board for high-frequency applications. Meanwhile, silicone gel has superior properties such as attaching/detaching, weather resistance, and human safety. If the PTFE and silicone gel can be strongly adhered to, they can be applied to internet of things (IoT) devices that can be attached and detached freely. However, adhesion between PTFE, which has poor adhesion, and silicone gel, which has low mechanical strength, is difficult and has not been reported. In this study, PTFE was modified with heat-assisted plasma treatment, and silicone gel was treated with oleophilic SiO powder to improve elastic modulus and modified with plasma jet treatment, and then bonded without adhesive. The adhesion strength of PTFE/silicone gel assembly was 1.13 N mm when treated moderately, but only 0.01 N mm when untreated and treated excessively. To investigate the factors causing the difference in the adhesion strength, the surface of silicone gel was evaluated by water contact angle measurement, Fourier transform infrared spectroscopy, and confocal laser scanning microscopy. When treated moderately, hydrophilic functional groups and cross-linking were most frequently increased. Furthermore, when treated excessively, surface degradation was observed, which was expected to lower the adhesion strength. The adhesive-free bonding between PTFE and silicone gel can open a new path for developing IoT devices that can be freely attached and detached.
聚四氟乙烯（PTFE）具有高频特性和低传输损耗，有望用作高频应用印刷线路板的基材。同时，硅胶具有诸如附着/分离、耐候性和人体安全性等优异性能。如果PTFE和硅胶能够牢固地粘合在一起，它们就可以应用于能够自由附着和拆卸的物联网（IoT）设备。然而，附着力差的PTFE和机械强度低的硅胶之间的粘合很困难，且尚未见报道。在本研究中，对PTFE进行热辅助等离子体处理改性，对硅胶用亲油性SiO粉末处理以提高弹性模量，并用等离子体射流处理进行改性，然后不使用粘合剂进行粘合。适度处理时，PTFE/硅胶组件的粘合强度为1.13 N/mm，但未处理和过度处理时仅为0.01 N/mm。为了研究导致粘合强度差异的因素，通过水接触角测量、傅里叶变换红外光谱和共聚焦激光扫描显微镜对硅胶表面进行了评估。适度处理时，亲水性官能团和交联增加最为频繁。此外，过度处理时，观察到表面降解，这预计会降低粘合强度。PTFE和硅胶之间的无粘合剂粘合可为开发能够自由附着和拆卸的物联网设备开辟一条新途径。
