Extended Data Fig. 4: Photopatterning process of NBR dielectric.
From: High-speed and large-scale intrinsically stretchable integrated circuits
a, Schematic diagram showing the process of patterning NBR dielectric. A reduction of peak intensity of the C-H stretching near 920 cm−1 from -C = C-H is an indicator of crosslinking of some of the vinyl groups. b, FT-IR spectrum of NBR-PETMP crosslinking reaction. The green shade marks the region for a zoom-in view on the right. c, OM image of the patterned NBR array. d, Thickness of NBR patterns versus exposure doses using different crosslinking approaches. Compared with the azide crosslinker (4 wt% vs NBR) that requires a 254 nm wavelength illumination and a high dose, PETMP (4 wt% vs NBR) based thiol crosslinker can induce NBR patterning using a 385 nm wavelength light source with a significantly reduced exposure dose. The error bars describe the standard error for three samples in each case.