Direct Metal Transfer\non Swellable Hydrogel with Dehydration-Induced\nPhysical Adhesion

Composites of hydrogels and metals are gaining interest\nbecause\nof each material’s unique properties. However, the stable adhesion\nof metals on hydrogels is challenging due to the mechanical mismatch\nat the soft–hard interface and the liquidity of the water components\nin hydrogels. We propose a facile physical-adhesion method that involves\nthe dehydration process of hydrogels to transfer metals from a glass\nsubstrate. This method is based on the hydrophobic interaction between\npolymer chains and metals and is stable, even in water. Continuous\nmetal wiring was achieved on a swollen hydrogel, and electrical conduction\nwas effective for a soft electronic device. Therefore, our method\ncould be a versatile method for integrating hydrogels and metals.