Rational Design of a Printable, Highly Conductive Siliconebased Electrically Conductive Adhesive for Stretchable RadioFrequency Antennas

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 464 wileyonlinelibrary.com fl exible nature, impossible within the confi nes of rigid and planar substrates. Stretchable RF electronics not only enable applications in which circuits can be wrapped conformally around complex curvilinear shapes or biological tissues, such as in body-worn wireless sensor nodes, [ 1,2 ] and wearable radio frequency identifi cation (RFID) tags, [ 3 ] but also allow facile tuning of the resonant frequency by mechanical deformation. [ 4,5 ] However, the fi eld of stretchable RF electronics is still in its infancy, and like other emerging electronic technologies, new materials and processing methods are the two driving forces for their ever-improving development and performance. There are currently two general approaches to the fabrication of stretchable electronics. The fi rst utilizes conventional rigid materials, but employs elegantly designed wavy or arc-shaped structures that are capable of accommodating applied strains of 100% or more. [ 2,6,7 ] The second approach is to maintain the conventional circuit layout, but embed stretchable or fl owable conductive materials, such as conductive polymers, [ 8,9 ] conductive polymer composites, [ 10 ]