The Effect of Electrostatic Force between the Nanoparticles and the Substrate on the Uniform Assembly of Inkjet-Printed Nanoparticles

Inkjet-printed functional nanoparticles are actively used in various engineering applications, including bioelectronic and chemical sensors. To maximize the functionalities of the nanoparticles, the printed nanoparticles must be uniformly assembled within the printed micro patterns. However, controlling the movement of the nanoparticles is challenging as it involves multiple mechanisms that play important roles. In this work, we propose an experimental methodology to independently vary the surface charge polarities of the nanoparticles and the printing substrates. We used this method to study the effect of the electrostatic forces between the nanoparticles and the substrate on the uniform assembly of the inkjet-printed nanoparticles during the drying of the inks. We confirmed that the attractive electrostatic force between the two is crucial in uniformly distributing the nanoparticles.