Microscale electrostatic 2D- and 3D-printing

Abstract: There has been an explosive interest in 2D- and 3D-printing production methods during the past decade due to the ability to rapidly create almost arbitrary structures. Challenges of printing control are encountered for instance when pushing the methods to produce smaller and smaller structures. Electrostatic printing methods ejects an ink from a nozzle onto the printing surface using a strong electric field. Distortions in the electric field causes the printing to behave in ways that may not be expected, and therefore decrease the control of printing of smaller structures. In the first part of the thesis we introduce a guiding electrode to actively correct the printing paths of the ejected material by changing the electric field. This technique was used to create 2D- and 3D-structures of plastic and increased the printing control when the guiding electrode was active.  The second part of the thesis is focused on using electrowriting to spray a suspension of graphene oxide to create thin films on substrates. The suspension will partially evaporate in the spray. The solid content of the suspension, the graphene oxide, undergoes folding and crumpling as the spray droplet size decreases due to solvent evaporation. Too little evaporation at close spraying distances will result in coffee-stain type of effects. We have shown the possibility to control the microstructure of the graphene oxide thin films by optimization of the spraying distance. The increased control in the electrowriting methods will allow us to create structures of supercapacitors for energy storage. We will use these methods to evaluate the possible electrical energy storage possible through microstructure optimization.