Profile improvement of blade coated circuits by the capillary force originating from the hydrophobic sidewalls

Abstract Restricting the diffusion of conductive inks plays a key role in printed electronics application. Micro-channels with different sidewall surface energies, which can be approximated as a capillary, are fabricated to restrict the blade-coated ink diffusion using both of the gravitational effect and the capillary force. The coffee ring effect of aqueous silver ink is inhibited by the capillary force when the hydrophobic sidewalls distance is no more than 50 μ m in this paper. As a result, the conductive lines with improved cross-sectional profiles are obtained by this method, with the typical resistivity more than 10 8 times lower than the measured results with hydrophilic sidewalls. The capillary force was also found to lose its effect when the width is larger enough, which needs surfactant addition to improve the silver film property. I–V curves of the original aqueous ink and the ink improved by traditional methods shows that the profile improvement by the hydrophobic sidewall can be used with other ink improving methods cooperatively. These studies open up the possibility of improving the printed conductive patterns by this method as an auxiliary tool used together with the traditional methods reported before.