Janus metallic film with gold and silver luster by electroless deposition of silver using poly(dopamine acrylamide) thin film

Abstract

Films that exhibit different metallic luster on the front and back, called Janus metallic films, have broad applications ranging from design materials to optical devices. However, the fabrication of these films is often a complicated process involving multiple metal deposition steps, thermal annealing, and calcination. Herein, we report the simple preparation of a Janus metallic film by electroless deposition of silver on a poly(dopamine acrylamide) (pDOPAm) thin film. pDOPAm was successfully synthesized via the controlled reversible addition–fragmentation chain transfer polymerization of dopamine acrylamide without a protective group using dimethylformamide as the solvent. The synthesized pDOPAm was spin-coated onto a solid substrate, which was then immersed in an aqueous AgNO₃ solution to achieve the electroless deposition of silver. Our preparation method will considerably simplify the fabrication of Janus metallic films, enabling their widespread application as decorative or authentication materials.