In their paper, the researchers note that such a cut-and-paste method can be used to pattern other material combinations, including Al/PET, carbon-doped thin film PDMS, graphene/PMMA and even indium tin oxide (ITO) on PET.
Once transferred, the 1.5μm-thick tape-free and open-mesh e-tattoo can adhere on the skin purely via van der Waals forces. For improved durability, it was sprayed with a transparent encapsulation layer about 1μm thick (except for the hydration sensors which had been covered by a paper stencil).
Due to their high conformability, these low cost e-tattoos ensure a large contact area between the sensors and the skin, lowering the contact impedance and facilitating signal transfer across the sensor–skin interface. Measuring 75×40mm, the multifunctional e-tattoo was shown to operate reliably even under various skin deformations.
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