Effect of PVP on fabrication of Cu nanoparticles using an electrical wire explosion method

Cu nanoparticles have several advantages such as their high electrical and thermal conductivity and low cost. Electrical wire explosion (EWE) method is one of the methods used to fabricate metal nanoparticles. The advantages of this technique are the high purity of the nanoparticles, ability to employ this technique in large-scale manufacturing, and high energy efficiency. In previous research, polyvinylpyrrolidone (PVP) was shown to prevent the agglomeration of metal nanoparticles. However, the effect of PVP on Cu nanoparticle synthesis using the EWE method has not been investigated. This study describes the effects of PVP on the size and shape of Cu nanoparticles made by the EWE method. Experiments were carried out with Cu/PVP colloids that were exploded by a current pulse voltage within a few microseconds. The experiment was conducted with various contents and molecular weights of PVP. Fabricated Cu nanoparticles were identified with field-emission scanning electron microscopy and high-resolution transmission electron microscopy. The size of the Cu nanoparticles was measured by the direct light scattering method. The smallest nanoparticles were about 21 nm and obtained when PVP with a molecular weight of 360,000 and content of 1.0 wt% was used. The shape of the nanoparticles changed from anisotropic to isotropic with increasing content and molecular weight of PVP. The electrical resistivity of printed Cu patterns decreased as the Cu nanoparticle get smaller.