Emeritus Professor, Institute of Physical Chemistry, Bulgarian Academy of Sciences (IPC BAS), Bulgaria

Biography: D.Sc. Stephan Armyanov is Emeritus Professor at the Institute of Physical Chemistry, Bulgarian Academy of Sciences (IPC BAS), being a specialist in materials science and electrochemistry. He graduated from Moscow Institute of Steel and Alloys in Russia. He joined IPC BAS, where he got his PhD and D.Sc. degrees and became Professor. He was a Visiting Scientist in USA and Belgium.

His research interests include the relations between deposition conditions, structure and properties of electroless and electrodeposited materials and their properties connected with special applications: magnetic behavior, internal stress, thermal stability of amorphous state, photo-catalytic activity, core-shell nano-catalysts for fuel cells, electroless deposition onto polymers.

S. Armyanov and his group have long-term collaboration with Universities in Belgium and Greece. His research work was connected with Bulgarian and international industry.

S. Armyanov is a member of the Electrochemical Society, International Society of Electrochemistry and International Association of Advanced Materials (IAAM). He is a recipient of IAAM Medal for 2017 and HEINZ-LEUZE-PREIS 1991 of the German Society for Plating and Surface Finishing.

Speech Title: Selective metallization of biocompatible poly(dimethylsiloxane) by electroless deposition after a laser treatment

Aims: To demonstrate selective electroless deposition of pure Ni and Pt into tracks on PDMS surface formed after laser treatment. The process eliminates the application of masks, as well as the usual chemical sensibilization and activation for plating on supports inert to this process.

Methods: SEM and computer μ-tomography are applied to investigate the morphology modifications of PDMS and deposited metals. μ-Raman spectroscopy, XPS analyses reveal changes in surface composition of PDMS during the laser treatment.

Results: The very first stable effect of laser beam absorption is to produce locally separation of the organic part of the molecular structure of PDMS from its inorganic counterpart. As a result of the laser treatment, beside the peaks of pristine PDMS in the Raman spectrum a sharp peak of crystalline silicon (c-Si) appears. The curve fitting of Si 2p and O 1s peaks, obtained by XPS, shows the oxidation degree that takes place during the laser irradiation. The morphology of the electroless deposited metal has specific features exposing nano-flowerlike shapes.

Conclusions: Efficient laser treatment requires specific irradiation energy absorption inducing surface chemical composition and morphology transformations. The metallization by electroless plating becomes possible on the formed patterns, where hydrophobic surface of the pristine PDMS is converted into hydrophilic tracks. In addition, their well-developed surface roughness enables good adhesion. Hydrazine reducer can be used to deposit pure electroless Ni and Pt on the laser irradiated tracks.