Guided selective deposition of nanoparticles by tuning of the surface potential

¹ Department of Chemistry and Chemical Engineering, Chalmers University of Technology Gothenburg 412 96, Sweden
² Nano-Science Center, Department of Chemistry, University of Copenhagen - Universitetsparken 5, 2100, Copenhagen, Denmark
³ Department of Microtechnology and Nanoscience, Chalmers University of Technology Gothenburg 412 96, Sweden

^(b) tue@nano.ku.dk
^(c) kasper.moth-poulsen@chalmers.se

Received: 7 June 2017
Accepted: 31 August 2017

Abstract

Guided deposition of nanoparticles onto different substrates is of great importance for a variety of applications such as biosensing, targeted cancer therapy, anti-bacterial coatings and single molecular electronics. It is therefore important to gain an understanding of what parameters are involved in the deposition of nanoparticles. In this work we have deposited 60 nm, negatively charged, citrate stabilized gold nanoparticles onto microstructures consisting of six different materials, (vanadium (V), silicon dioxide (SiO₂), gold (Au), aluminum (Al), copper (Cu) and nickel (Ni)). The samples have then been investigated by scanning electron microscopy to extract the particle density. The surface potential was calculated from the measured surface charge density maps measured by atomic force microscopy while the samples were submerged in a KCl water solution. These values were compared with literature values of the isoelectric points (IEP) of different oxides formed on the metals in an ambient environment. According to measurements, Al had the highest surface potential followed by Ni and Cu. The same trend was observed for the nanoparticle densities. No particles were found on V, SiO₂ and Au. The literature values of the IEP showed a different trend compared to the surface potential measurements concluding that IEP is not a reliable parameter for the prediction of NP deposition.