Pretreatment and deposition process of electroless Ni plating on polyimide film for electronic field applications

Efficient and Adhesiveless Metallization of Flexible Polyimide by Functional Grafting of Carboxylic Acid Groups

Surface metallization of polyimide (PI) is the key process for the preparation of flexible printed circuit boards (FPCBs). To meet the miniaturization demand, the ultrathinness of FPCB by the removal of the intermediate adhesive layer is imperative. The common adhesiveless process relies on the surface activation of hydrophobic PI through alkaline hydrolysis to generate the hydrophilic carboxylate anion sites for the metallic deposition. However, the alkaline hydrolysis process involves the imide ring cleavage caused by the attack of a strong nucleophile (OH^-), resulting in mechanical destruction and surface coarseness of PI. In this study, a new PI is synthesized with the grafting of carboxylic acid groups as the active sites to intrinsically activate PI for efficient metallization. The surface activation is accomplished through an acid-base neutralization reaction in a dilute alkaline environment, which can suppress the alkaline hydrolysis reaction. The attenuated total reflection Fourier transform infrared spectroscopy analysis confirms a significant reduction of the extent of the imide ring cleavage in the carboxylic acid-grafted PI films. According to the microstructural examination using transmission electron microscopy, the deposited metal film adheres firmly to the carboxylic acid-grafted PI films through an interlocking effect of a broccoli bud-shaped nanocluster layer.

Extremely low catalyst loading for electroless deposition on a non-conductive surface by a treatment for reduced graphene oxide

Enhancement of electroless deposition using reduced-graphene-oxide (rGO) coating for a conductive surface on the non-conductive substrate is proposed and demonstrated. We confirmed that the rGO treatment enhanced the Pd catalytic activity and achieved a sufficient rate in electroless deposition with extremely low Pd loading (3.94 × 10^-2 μg cm^-2).

Graphene oxide reinforced Ni–P coatings for bacterial adhesion inhibition

Bacterial adhesion on the surfaces of medical devices, food processing equipment, heat exchangers and ship hulls has been recognized as a widespread problem.