Abstract
AbstractIn the conventional polyol method, addition of extra reducing agent or reacting at high temperature is needed to accelerate the reduction rate. However, our investigation shows stable and uniform Pd nanoparticles protected by polyvinyl pyrrolidone (PVP) can be successfully synthesized in pure ethylene glycol (EG) under room temperature by adding of NaOH to speed up the reduction.The average particle size of the so-obtain Pd nanoparticles ranges from 8.6 to 2.4 nm when the NaOH changes from 0 to 3.2×10-1 M. The particle formation was monitored by UV-Vis. And the microstructure of Pd nanopartilces was analyzed by TEM and XRD. The product of adding NaOH in EG was characterized by FT-IR and compound having –CHO group was identified, which possesses reductive ability and proves that adding NaOH in EG can indeed accelerate the reduction of Pd.The newly developed Pd nanoparticle was tested to be an effective activator for electroless cooper deposit and especially for PTH processing in the PCB industry. The Pd/PVP/EG based activator shows not only superior stability but also improved performance compared with existing commercial activators. Suitable conditioning procedures for the newly synthesized activator were also developed.