Because Invisicon® nanotube and binder inks can be formulated to have a wide range of viscosity and solids content, there are a variety of ways to deposit coatings. We have successfully demonstrated a range of these coating technologies for different customers. Coatings printed using different techniques result in the same optoelectronic performance. Because nanotube and binder inks are deposited in a two-step process, coating methods can be mixed and matched to best suit the properties of each ink, substrate, and application.
Spray Coating is a simple way to batch-coat substrates of arbitrary geometries. Eikos utilizes a custom-built ventilated spray coater with a temperature controlled, X-Y rastering platen. Low viscosity nanotube inks are coated onto flat and curved substrates over a wide range of conductivities. Substrates with low surface energy, such as PTFE and PMMA, are well-suited to spray coating. Spray coated films are highly uniform across the substrate, and edge trimming is not required. Patterned films are made simply by using a shadow mask during deposition.
Dip Coating is a robust technique for coating glass and plastic sheets with uniform, thin films. Eikos employs dip coating to deposit nanotube and binder inks onto multiply curves surfaces and for uniform optical coatings.
Flow Coating is a coarse method to apply thicker films of nanotube and binder inks. Flow coating an insulating binder on top of a nanotube film will electrically isolate the nanotube film from its environment. Flow coated nanotube films can be used in EMI shielding or as a transparent wire.
Slot Die Coating is used to create uniform roll-to-roll coating of plastic films with high web speed. Eikos has demonstrated roll-to-roll slot die coating on commercial coating lines using specially formulated inks. In house, we use a draw-down coater, which simulates the coating conditions of a slot die and allows batch production of coated films. View a video of the process of coating with Invisicon ink.
Gravure Coating has been successfully demonstrated with high viscosity nanotube inks on 20” webs of PET. Gravure coating is versatile because it also enables direct patterning of coatings by choosing how the gravure roller is etched. Binder inks also are well-suited for roll-to-roll gravure printing.
Inkjet Printing has made major advances. Eikos employs a Unijet UJ100 inkjet printer for making transparent and conductive patterns onto plastic, glass, and devices. Using drop-on-demand printing, exceptionally fine patterns can be printed. Optical alignment allows patterned coatings to be deposited onto contact pads and active device elements. Inkjet printing allows device manufacturers added flexibility for rapid prototyping. Devices can be designed in CAD, printed, and tested within hours, rather than days or weeks. View a video of Eikos’s inkjet printer.
Several other printing techniques are under development at Eikos. If you have a special need for your application, please contact us.