Effect of viscoelasticity on liquid transfer during gravure printing

Gravure printed PEDOT:PSS as anode for flexible ITO-free organic light emitting diodes

“…Therefore, the printed layers should be defect-free, uniform and homogeneous with very controlled thicknesses [6][7][8]15]; very low roughness is also a crucial feature since the morphology of the previous printed layers can influence the properties of the successive layers [14]. In order to further improve the quality of the produced layer with the aim to prove it as anode into an OLED, increasing the printing speed was here tried without changing ink (viscosity, solvent) and other process parameters (cells geometry, nip pressure), looking for the optimal conditions of the ink transfer step [12,[15][16][17]. In Table 1 the characteristics of the printed anodes are showed and compared with the ones of the anode obtained by spin coating.…”

Numerical study of printing ink structuring

“…A number of works are devoted to the study of structuring of printing ink in gravure printing. In particular, the transfer of the printing ink from the idealized cell of the form [2], the influence of the constricting shift on the ink transfer from the gravure print cell [3], the influence of the viscoelastic properties of ink [4,5] is investigated. During a flat offset printing machine operation, the circulating movement of ink is formed in an ink can (Fig 1).…”

The effect of shear-thickening on liquid transfer from an idealized gravure cell

“…This technology enables the fabrication of thin organic, inorganic and mixed organic/inorganic films with nanoscale patterns at high resolution for devices in wide applications such as, solar cells, thin film transistors, organic light emitting diodes, biosensors and biodevices [3][4][5][6][7][8]. Gravure printing is a roll-to-roll processing technique used to coat/print thin films less than 50 lm for a wide variety of applications in high volumes such as magazines, packaging, flexible electronics, greeting cards and tapes [9][10][11][12]. In gravure process, a roller with desired engraving, typically in microns dimensions, is passed through an ink reservoir and the excess is metered off by passing by a doctor blade.…”

“…There have also been studies both experiments and computations dedicated to the influence of viscoelasticity on gravure printing [38,10,39]. Ahn et al [38] examined the influence of elasticity through numerical computations using Oldroyd-B model and observed significant differences in the velocity field and pressure distribution in the cavity between viscoelastic and Newtonian fluids.…”