A facile fabrication method of silver lines on PET with good adhesion at room temperature

Flexible/foldable electronics will undoubtedly attract an increasing research interest in the future. Here we demonstrate a facile method to fabricate tunable micro-patterned silver line on PET film with good substrate adhesion based on mussel-inspired surface modification. The PET substrate was first modified with a catecholic adhesive layer by dip-coating in aqueous solution of dopamine at alkali condition for ten minutes. Then combination of photolithographic approach poly(dopamine) (PDA) pattern was developed on the PET film. Finally, silver was deposited only on the exposed PDA regions of the PET substrate by electroless plating without any catalyst or seed layer. This site-selective deposition process enabled the good adhesion of silver line on the flexible polymer substrate due to the multifunction of PDA, which acted as both affinity binder and reduction reagent. The silver lines thickness was uniform and their borders were smooth. Furthermore, the sheet resistance of the silver line was as low as 1.2 Ω/□ and didn´t show distinct alteration under foldable state.