The effect of viscosity and surface tension on inkjet printed picoliter dots

Abstract

In this study, we investigated the effect of liquid viscosity and surface tension for inkjet printing on porous cellulose sheets.

Inkjet‐Printed Compact TiO2 Electron Transport Layer for Perovskite Solar Cells

“…Considering a nozzle diameter of 9 μm, a speed of the droplets estimated at ≈8 m s −1 , and an ink density considered to be closed to the density of pure IPA (i.e., 0.786 kg m −3 ), the Oh number value was found to be at 0.51, and the Re number value was estimated at 28, confirming the printability of the TAA:IPA inks. [ 24 ] The contact angle measured between the soda lime glass (SLG)/FTO substrate and the ink remained unchanged for the different ink formulations (i.e., ≈13°, close to the pure IPA–FTO contact angle value, while the pure TAA–FTO contact angle value was 21°), showing a good wettability of the surface and a good spreading of the ink (see Figure S2, Supporting Information). The optimal drop‐spacing value (i.e., the distance between the center of two adjacent droplets on the substrate) has been empirically determined at 30 μm (see Figure S5, Supporting Information), to reduce droplet overlap while avoiding the formation of noncovered areas.…”

Recent Advances in High-Throughput Nanomaterial Manufacturing for Hybrid Flexible Bioelectronics

“…The fluid mechanics during printing is characterized primarily by three dimensionless quantities, the Weber number (We), Reynolds number (Re), and Ohnesorge number (Oh): where η , ρ , and γ are the ink viscosity, density, and surface tension, respectively, v is the print velocity, and ζ is characteristic printing length, which is in most cases simply the diameter of the print head nozzle [ 25 , 26 , 70 ]. In almost all inkjet applications, Oh must be between 1 and 1/10 to achieve a quality print, as illustrated in Figure 5 b [ 28 ]. At high Oh values, the ink viscosity will prevent stable drop formation [ 28 ].…”

“…In almost all inkjet applications, Oh must be between 1 and 1/10 to achieve a quality print, as illustrated in Figure 5 b [ 28 ]. At high Oh values, the ink viscosity will prevent stable drop formation [ 28 ]. When Oh is too low, the ink forms many uncontrolled drops instead of a single, well-defined drop, which results in an unusable print [ 28 , 69 ].…”

“…In contrast, contact printing methods, such as screen, gravure, flexographic, slot die, and doctor blade printing are easily integrated with high throughput roll to roll systems, making them an excellent option for industrial scale hybrid bioelectronics manufacturing. A summary of each of the high throughput nanomaterial fabrication methods discussed in this review is provided in Table 1 [ 17 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ].…”

Synthesis of Printable Polyvinyl Alcohol for Aerosol Jet and Inkjet Printing Technology

“…The surface tension is found to be 42.03 mN/m for Kapton and 32.51 mN/m for Silicon substrate. To achieve a good inkjet printing with any material, the surface tension has to be in between (25-75) mN/m and viscosity has to be in between (1-8)cP [44]. Table 2 shows the summary of contact angles on Kapton and Silicon for all five concentrations of PVA.…”