Flexible Thermoplastic Conductive Adhesive with High Reliability

Isotropically conductive adhesives (ICAs) have always been a hot spot in producing UHF RFID tag antennas with low cost for mass-production and low conductor loss.[1] As an interesting motif of flexible electronic component, they can also be integrated into sensors or as biocompatible electronic components in tissue engineering applications.[2] Considering the cost-effectiveness and the requirements for making those devices which can remain high conductivity under external stress forces, polyurethane (PU) is an interesting motif for making the dispersant material, as it can provide maximized elongation at break, moisture resistance, and excellent impact resistance and reliability. They are also safe to human health, which have a blooming market in tissue regeneration materials.[3, 4] Severe deformation of the matrix can result in the rearrangement of the conductive silver fillers, which can result in the variation of the electrical resistivity of the elastic ICA. Based on our prior research work on the ultralow silver filling rate of ICAs, we evaluated the electrical performance of the elastic ICA materials and their mechanical properties.[5] From the experimental result, we observed that the ICAs with this elastic polymer dispersant showed stable electrical resistivity after aging for 168 hours and even at low filler content level (e.g. 30%). Read range of the RFID tags showed that these ICAs are feasible for printed antennas.