In situ synthesis of Ag-acrylic nanocomposites: Tomography-based percolation model, irreversible photoinduced electromigration and reversible electromigration

We present a study related to a polymeric matrix nanocomposite system, specifically conceived for the realization of inkjet printed resistive tracks for passive components on flexible substrates. In particular this composite is liquid at room temperature, water based and of safe use, UV-curable and easily processable, ready for industrial production. The matrix is a UV-curable resin (polyethylene glycol diacrylate, PEGDA); the dispersoid is a controlled amount of Ag nanoparticles (NPs), produced either in situ during photopolimerization, by means of a silver hexafluoroantimonate precursor, or ex situ starting from a commercial Ag-nanoparticle-based ink. The effects on the electrical properties produced by ageing, synthesis conditions and geometry are considered; size distribution, density and distance between NPs have been addressed and correlated to the electrical properties. A three-dimensional extension of percolation theory based on the geometrical properties of samples, as deduced from secondary electron tomography, is given. Interesting conclusions are drawn and light is cast on the NP nucleation and growth and electromigration mechanisms. Applications as electrochromic material or resistive element are foreseen.