%I IMAPS - International Microelectronics Assembly and Packaging Society %L discovery10190389 %J Advancing Microelectronics %K life test, encapsulation, printed circuit board, impedance, FR4, solder %X Silicone encapsulated FR 4 printed circuit boards may provide a rapid solution for protecting pre-clinical prototype implant electronics. Interdigitated electrodes (IDE s) with and without solder coating were manufactured on Cu-FR 4 laminates and silicone encapsulated (N = 14). IDE s were aged in saline and change in impedance was measured. Solder coated IDE s had stable 1 kHz impedances throughout the aging period with promising lifetimes for pre-clinical prototypes. A single uncoated IDE failed with a fall in impedance and verdigris. Other uncoated IDEs showed increasing impedance and dark copper(II) oxide. Failures attributable to contaminants and moisture ingress are under investigation. %O This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. %A I Ali %A F Xue %A CP Henriquez %A T Niederhoffer %A AS Idil %A DJ Iang %A HT Lancashire %V 2023 %T Initial L ife Test of Silicone E ncapsulated FR 4 Printed Circuit Boards for Pre-Clinical A ctive Implants %B IMAPSource Proceedings 2023 (EMPC) %N EMPC %P 224-227 %D 2024