On‐Demand Laser Printing of Picoliter‐Sized, Highly Viscous, Adhesive Fluids: Beyond Inkjet Limitations

Abstract

Novel printing methods represent a class of emerging technologies, with applications ranging from biomedical to energy devices, attracting significant attention because of their ability to handle new classes of materials. Typically, popular printing technologies, such as inkjet printing, deposit low‐viscosity inks (1–15 mPa s). In a broad range of emerging applications, alternative printing techniques will enable the handling of materials with much higher viscosities. Here, Laser‐induced forward transfer (LIFT) is employed as a direct, nozzleless printing method, enabling the processing of fluids with viscosities far beyond the inkjet printing regime. Specifically, exploiting the capability of LIFT being a high‐speed processing technique, maintaining at the same time high printing resolution, the printing of highly viscous cyanoacrylate adhesives (from 30 to 1700 mPa s) is demonstrated achieving printing resolution down to 30 µm. The volume of the LIFT‐ejected adhesive droplets lies in the picoliter scale. As a further advantage compared with inkjet techniques, the printing resolution can be tuned on demand by adjusting the laser fluence during the process. Finally, as an application example, the attachment of chemical indicator powders (i.e., dimethylglyoxime powder) on printed adhesives patterns is illustrated, creating heavy metal sensors with remarkable fabrication facility.

Facile and Low-Cost SPE Modification Towards Ultra-Sensitive Organophosphorus and Carbamate Pesticide Detection in Olive Oil

“…Spotting with the use of the LIFT technique introduces two further significant advantages in comparison to drop-casting. On the one hand, the amount of deposited material can be minimized, thereby reducing the cost of sensor fabrication [ 44 ], while at the same time high spatial resolution can be achieved [ 45 ], which renders it ideal as a technique for the biofunctionalization of sensor surfaces of minute dimensions.…”

Laser‐Induced Forward Transfer of High Viscous, Non‐Newtonian Silver Nanoparticle Inks: Jet Dynamics and Temporal Evolution of the Printed Droplet Study

“…Then, the high‐pressure gas bubble expands, impelling the supernatant ink film away from the donor. When the internal bubble pressure becomes lower than the external, the bubble collapses into a jet of ink propagating toward the receiver, with the rheological properties of the ink determining the jet's morphology and evolution . Finally, when it reaches the receiver substrate, a droplet is formed, whose final dimensions are determined by the rheological properties of the ink, as well as the wetting properties and roughness of the surface.…”

Drop impact printing

“…This in turn increases the cost and complexity of the setup. Emergence of other printing techniques [6][7][8][9] has also taken place using acoustic 10 , electrohydrodynamic (EHD) [11][12][13] , laser-assisted 14 , or microfluidics 15 based designs. Use of complex technology in these techniques prohibitively increases their setup and operational cost 16,17 .…”