Gold metallization of hybrid organic-inorganic polymer microstructures 3D printed by two-photon polymerization

• Published in: Surfaces and interfaces 2023-07, Vol.39, p.102895, Article 102895
• Main Authors: Bretosh, Kateryna, Hallais, Simon, Chevalier-Cesar, Clotaire, Zucchi, Gaël, Bodelot, Laurence
• Format: Article
• Language: English
• Subjects: 3D printing; Chemical Sciences; Electrical conductivity; Electroless plating; Engineering Sciences; Hybrid organic-inorganic polymer; Metallic coating; Micro and nanotechnologies; Microelectronics; Polymers; Two-photon polymerization
• ISSN: 2468-0230; 2468-0230
• DOI: 10.1016/j.surfin.2023.102895

•A strategy was established to coat printed hybrid polymer microstructures with gold.•The influence of procedure parameters on the gold layer quality were investigated.•The morphology, thickness and conductivity of the gold layers were characterized.•Electrical conductivities higher than half that of bulk gold can be reached.•This conformal method can be used to coat micrometric structures of arbitrary shapes. Two-photon polymerization is a femtosecond laser-based technique enabling printing of three-dimensional structures down to submicron resolution within photocurable polymers. Rendering the dielectric 3D printed structures conductive can be of great benefit for various applications in domains such as energy, photonics, or multifunctional devices. In this work, the microstructures of interest are made of a silicon-zirconium hybrid organic-inorganic polymer exhibiting low shrinkage during development. A simple and efficient metallization method by electroless plating is investigated to deposit a gold layer on the surface of the printed microstructures. The influence of the method parameters on the quality and properties of the deposited layer is studied. Among these parameters, the surface modification agent concentration and step duration, as well as the seeding solution concentration, must be adapted to the specific case of the considered hybrid microstructures. The concentration of metal ions in the plating bath is the most influential parameter on the morphology of the deposited gold layers. In particular, higher concentrations lead to smooth and continuous layers with electrical conductivities higher than half that of bulk gold. Finally, the deposited layers are shown to coat 3D printed microstructures of arbitrary shapes, thus confirming the conformality of the method at the micrometric scale. [Display omitted]