Study of Surface Metallization of Polyimide Film and Interfacial Characterization

Abstract

Nickel (Ni) metallization of polyimide (PI) was performed using a solution-based process including imide-ring opening reactions, the implanting of Ni ions, the reduction of catalytic Ni nanoparticles, and the electroless deposition of a Ni film. The start-up imide-ring opening reaction plays a crucial role in activating inert PI for subsequent Ni implanting and deposition. A basic treatment of potassium hydroxide (KOH) is commonly used in the imide-ring opening reaction where a poly(amic acid) (PAA) layer forms on the PI surface. In this study, we report that the KOH concentration significantly affects the implanting, reduction, and deposition behavior of Ni. A uniform Ni layer can be grown on a PI film with full coverage through electroless deposition with a KOH concentration of 0.5 M and higher. However, excessive imide-ring opening reactions caused by 5 M KOH treatment resulted in the formation of a thick PAA layer embedded with an uneven distribution of Ni nanoparticles. This composite layer (PAA + Ni) causes wastage of the Ni catalyst and degradation of peel strength of the Ni layer on PI.

RGO-Protected Electroless Plated Nickel Electrode with Enhanced Stability Performance for Flexible Micro-Supercapacitors

“…The superior properties of MSCs are attributed to the high mechanical stability of EN/GC. The timid physical contact and the possible chemical bonds existing between EN and rGO can bear the large stresses generated during the bending process and satisfy the requirement of the high flexible electrodes. , In addition, the seed layer produced by SMIE and the electroless plating layer are of the same material, and this is beneficial to decrease the interface stress which can improve the interface adhesion. ,, …”

“…31,47 In addition, the seed layer produced by SMIE and the electroless plating layer are of the same material, and this is beneficial to decrease the interface stress which can improve the interface adhesion. 14,19,24 Good electrical and mechanical performances of MSCs obtained are probably attributed to several aspects: First, EN itself offers the relative electrochemical stability over deposited Ag and Cu by PVD or other chemical solution methods. Second, unlike the traditional seeding layer via an activation/ sensation process, in this study, the seed layer via SMIE is grown from the bulk of PI.…”

“…[10][11][12][13]16 Metallization can be realized by several techniques, like vacuum vapor deposition, arc and flame spraying, and plating. 8,13,14 Plating, both electroplating and electroless plating, as low temperature and all-solution techniques, is more effective than other techniques in terms of adhesiveness, cost, and batch fabrication. 7,11,15 Especially, the electroless plating has several additional advantages, such as the higher quality of deposition films, the flexibility of plating thickness, the suitability for arbitrary shape materials, etc.…”

“…Metallization is the key technology for fabrication of PI-based MSC electrodes. The most commonly deposited metals on PI include silver, copper, nickel, and so on. − , Metallization can be realized by several techniques, like vacuum vapor deposition, arc and flame spraying, and plating. ,, Plating, both electroplating and electroless plating, as low temperature and all-solution techniques, is more effective than other techniques in terms of adhesiveness, cost, and batch fabrication. ,, Especially, the electroless plating has several additional advantages, such as the higher quality of deposition films, the flexibility of plating thickness, the suitability for arbitrary shape materials, etc . For MSC applications, the electrochemical stability of the metallization layer in the electrolyte is an important topic to be considered …”

An Assessment of Surface Treatments for Adhesion of Polyimide Thin Films

“…Here, the reaction between the polymer and the solution yields to the opening of the imide ring. For metal deposition, this procedure is combined with proper ion exchange and reduction reactions [21][22][23]. In a similar fashion, amine solutions can also promote metal adhesion on PI films [11].…”