With the equipment of AFS Entwicklungs + Vertriebs GmbH, NORCOP demonstrates the significance of the surface chemistry of polymer substrates used in conductive ink screen printing, and how its modification by MOLECULAR COATING™ achieves low resistivity, defect-free, reliable, and compact flexible electrical circuits.
"MOLECULAR COATING™ is a plasma-induced surface deposition technology allowing the deposition of transparent thin coatings on the surface of various 2D plastic, paper, and textile substrates. It performs exceptionally well in screen printing of conductive inks, while preliminary results using inkjet printing have been very promising. When the right ink-substrate pair has been identified and used, the main characteristics of these thin layers are surface roughness and surface chemistry control, which lead to perfect wetting (zero pinholes) and adhesion. These characteristics afford the printer the following benefits:"
Absence of PINHOLES leads to increased conductivity in electrical circuits: often more than two times higher when compared to those printed on standard commercial PET.
Surface Roughness Control, achieved by varying the thickness of the deposited film, impacts the adhesion of the ink due to modification of the ink-substrate interlocking mechanisms (@Van Der Waals interactions)
Surface Chemistry Control, achieved by the introduction of carefully selected chemical functions on the surface of the substrate, ensures high energy covalent bonding between the MOLECULAR COATING™ and the resins present in the ink. These in turn affect:
The adhesion of the MOLECULAR COATING™ with the base substrate (PET or other)
Adhesion of the MOLECULAR COATING™ with the printed ink
Adhesion of the MOLECULAR COATING™ with the dielectric varnish
The resistance to deformation upon repeated bending (flexible organic coating)
The resistance to heat defects which occur during circuit operation (hot spots)
"The systems used in printing with metal-containing inks, circuits printed on NORCOP's substrates show narrow lines, 30-500 µm in width which is straight, with regular edges and constant interline spaces all along the tracks. In this way, the risks of circuit failure or short circuit formation are eliminated."
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