Full text loading...
Architecture of stretchable electronic circuits. (a) Cross-sectional view of a previous design. Stiff (nondeformable) platforms are deposited on top of the stretchable substrate. Electronic devices are built or transferred onto the platforms and interconnected with elastic wiring. (b) Cross-sectional view of the alterative design. Stiff platforms are embedded within the stretchable substrate. Electronic devices are manufactured directly onto the flat, elastomer surface, above the stiff platforms, and interconnected with elastic wiring.
Stretchable alumina disks on engineered elastomeric substrate. Top-view optical images recorded during a stretch cycle to 20% applied strain of (a) a 150 nm thick, 1 mm diameter, Al2O3 disk deposited onto 0.1 mm thick, bulk PDMS substrate and interconnected with a thin metal conductor (5/25/5 nm Ti/Au/Ti thin films); scale bar: 200 μm; (b) a 150 nm thick, 0.75 mm diameter, Al2O3 disk deposited above 1 mm diameter, 50 μm thick SU8 platform embedded in the 0.1 mm thick PDMS substrate and interconnected with a thin metal conductor (5/25/5 nm Ti/Au/Ti thin films); scale bar: 200 μm. (c) Electrical resistance as a function of time of the metallic conductor running across 5 Al2O3 disks on engineered substrate during 100 stretch cycles to 20% strain.
Surface strain mapping. (a) Experimental strain mapping at the top surface of the engineered substrate. A 20% macroscopic strain is applied along the x-axis. 50 μm thick, 1 mm diameter SU8 platforms are embedded at the bottom of the PDMS membrane. The platforms' spacing S varies from 2 mm to 10 mm; (left) top view, optical images and (right) colored strain maps. (b) Strain profiles taken along the x-axis from the center of the SU8 platform. (c) Corresponding 3D, finite element, simulated profiles.
Computed strains. (a) 3D FEM simulation of a quarter of a 50 μm thick, 1 mm diameter SU8 platforms are embedded at the bottom of the PDMS membrane. The platform spacing is 5 mm. Inset: localized, non-homogeneous strain distribution along the thickness. The 3D simulation can be decoupled in two complementary 2D models: (b) top view 2D in-plane stress model and (c) cross-section 2D in-plane stress model. (d) Strain profiles: the decoupled simulations can catch the asymptotic behavior of the 3D simulation (S/D = 6). (e) Surface strain profile. (f) Cross-section model profiles. (g) Cross-sectional schematic illustrating the penetration depth. (h) Penetration depth as a function of the PDMS thickness above the platform.
Article metrics loading...