Liquid dispensing and writing by a nano-grooved pin

TL;DR

This paper introduces a nano-grooved pin method for liquid dispensing and writing at micro/nano scales, offering a simpler, cheaper, and clog-resistant alternative to traditional nozzle-based techniques, with precise control over droplet and line sizes.

Contribution

The study presents a novel nano-grooved pin technology for liquid dispensing and writing, expanding capabilities in size control and material applicability while reducing complexity and cost.

Findings

Droplet diameters controllable from microns to 150 nm

Line heights as low as 5 nm achieved

Nano-grooved pins are simpler and cheaper to fabricate

Abstract

Liquid dispensing and writing in the extremely small size regime are important for applications in many current technologies, such as micro/nano fabrication, biological/chemical patterning and analysis, and drug discovery. Most of current dispensing/writing methods can be sorted into a category of liquid flowing through tiny tubes or nozzles that requires inputting an impulse energy, which leads to complex procedures, expensive equipment and narrow material applicability, especially for biomaterials. Here, we report a method that may lead to a new category: liquid flows over the tapered surface of a pin with longitudinal nano grooves on the surface to uninterruptedly perform droplet dispensing and direct writing. The dispensed droplet diameters were controllable from several microns down to 150 nm, and the written line heights were as low as 5 nm. The mechanism underlying automatic liquid storage on conical surface and spontaneous liquid transport through nano grooves is revealed and well modeled by a simple relationship. Furthermore, the nano-grooved pins are much simpler and cheaper in fabrication than nanoscale tubes and nozzles, and pins have much depressed clogging problems that are typically troublesome for tubes and nozzles. Our new strategy may constitute a basis for creating liquid dispensing/writing technologies that are simultaneously smaller, simpler, faster and applicable for more types of materials.