A different route to stretchable structures in which thick bar geometries replace thin ribbon layouts to yield scissor-like deformations instead of in- or out-of-plane buckling modes was studied. The findings demonstrate that scissor-like mechanics represents an important design approach that can complement previously reported schemes in stretchable electronics, where high elastic stretchability, high areal coverages of active devices, and high electric performance can be achieved simultaneously. More generally, systematic studies involving experimental work, FEA and analytical theory reveal three different deformation modes, wrinkling, buckling and scissoring, for serpentine structures of hard materials on soft elastomeric substrates. For otherwise comparable designs, the elastic stretchability in the scissoring regime is much higher than that in other two regimes. Analytical studies of these designs identify key geometric parameters that govern the elastic stretchability and yield optimal values for metallic serpentine interconnects that reach levels of stretchability up to 350%, roughly six times larger than previously reported values when prestrain is not applied. The scissoring physics depends only on the thickness/width aspect ratio, and the stretchability is reversely proportional to the width. As a result, designs that involve thin interconnects with comparable (small) widths represent optimal options to achieve both large stretchability and large flexibility. The scissoring design also provides low electrical resistance and efficient heat dissipation in interconnect structures due to their thick geometries.
Bibliographical noteFunding Information:
Y.S. acknowledges the support from Chinese Academy of Sciences via the ?Hundred Talent program?, the National Science Foundation of China (NSFC, No. 11572323), and the State Key Laboratory of Structural Analysis for Industrial Equipment at Dalian University of Technology (No. GZ1603). X.P. acknowledges the support of NSFC (No. 51365013) and the Natural Science Foundation of Jiangxi Province of China through grant No. 20133ACB21002. J.W.L. and U.P. thank the GRL Program (K20704000003TA050000310) through the NRF funded by the Ministry of Science. S.W. acknowledges the support from the ASME Applied Mechanics Division-Haythornthwaite Foundation Research Initiation Grant, and partial support from the NSFC (Nos. 11272260, 11172022, 11572022, 51075327, and 11302038). Y.H. acknowledges the support from NSF (DMR-1121262, CMMI-1300846, CMMI-1400169, and IIP-1534120). J.A.R. acknowledges supports from the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award # DE-FG02-07ER46741.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering