Improvement of Adhesion and Reliability of Conductive Inks on Flexible Liquid Crystal Polymer Substrates

The emergence of printed electronics as an industry has been growing and recognized in application areas such as antennas, RFID, displays, and photovoltaic cells. Paramount to the success of these devices is reliable conductive inks that adhere to the substrate after successive bending and stretching and maintaining a constant resistance with time. Furthermore, for high performance electronics, new substrates will be required that allow RF performance deep into the GHz regime. This paper describes an evaluation of commercially available inks on Kapton (R) and Liquid Crystal Polymer (LCP). Kapton (R) is a well known substrate in printed electronics and previous reliability evaluations have shown inks are generally formulated to adhere well to this substrate. LCP is a relative new material in the electronics industry and this study shows that additional pre-processing of the substrate is necessary to obtain similar reliability and adhesion performance as compared to Kapton (R).