Extended Data Fig. 4: Advantages of BIND connections.

a, b, Schematic (a) and photo (b) showing two patterned BIND interfaces (on module A and B) are joined face-to-face via BIND connection. Inset in b: The BIND connection is electrically conductive to light an LED. c, BIND connections expanded to other conductive materials such as silver/silver and silver/gold connections also display robust electrical and mechanical stretchability. d, Photo of a soft module connected to a flexible PI module patterned with 6 electrode channels, via soft-rigid BIND connection. e, Soft-rigid BIND connection involving rigid or flexible substrates like PI, PET, glass, and metal show higher electrical (~200%) and mechanical (~800%) stretchability than conventional connection via various commercial pastes. f, Interfacial toughness of SEBS encapsulation layer on a BIND interface (0.24 N/mm) is much larger than various other types of encapsulation layer bonded on a conventional PDMS/Au interface. All encapsulation layers are ~100 μm thick. g, SEM image of BIND encapsulation (~300 nm) on a pair of electrodes, exposing two pads for signal collection (SEM shown in magnified view). Scale bar in g: 100 µm. h-j, Resolution of single BIND interface, BIND connection, and BIND encapsulation can achieve 100 µm. The electrical stretchability of both BIND interface (h) and BIND connection (i) decreases with reduced line width, while the mechanical stretchability was kept relatively stable. The overall width was kept as 5 mm. Inset: SEM image of BIND encapsulation with exposed area of 100 × 100 µm². Scale bar: 50 µm. Error bars are s.d. from 3-4 samples.