Electrohydrodynamic Direct-Writing Micropatterns with Assisted Airflow

Abstract

Electrohydrodynamic direct-writing (EDW) is a developing technology for high-resolution printing. How to decrease the line width and improve the deposition accuracy of direct-written patterns has been the key to the promotion for the further application of EDW. In this paper, an airflow-assisted spinneret for electrohydrodynamic direct-writing was designed. An assisted laminar airflow was introduced to the EDW process, which provided an additional stretching and constraining force on the jet to reduce the surrounding interferences and enhance jet stability. The flow field and the electric field around the spinneret were simulated to direct the structure design of the airflow-assisted spinneret. Then, a series of experiments were conducted, and the results verified the spinneret design and demonstrated a stable ejection of jet in the EDW process. With assisted airflow, the uniformity of printed patterns and the deposition position accuracy of a charged jet can be improved. Complex patterns with positioning errors of less than 5% have been printed and characterized, which provide an effective way to promote the integration of micro/nanosystems.

Two Sides of Electrospun Fiber in Promoting and Inhibiting Biomedical Processes

“…In near‐field electrospinning, the distance between the spinneret and the grounded collector is less than 5 cm, which makes it easier for the jet to hit the collector in a straight line. [ 59 ] Near‐field electrospinning demonstrates specific advantages compared to far‐field electrospinning, such as: i) a lower voltage that averts the economic and safety problems of using high voltages; ii) a movable spinneret or collector such that the fibers can be collected before bending; and iii) more uniform fiber production on the collector, which leads to a high utilization rate of the raw materials and is beneficial for obtaining a uniform electrospun product. However, near‐field electrospinning has limitations as a result of its relatively low flow velocity and large fibers compared to far‐field electrospinning.…”

Jet Mode Recognition of Electrohydrodynamic Direct-Writing Based on Micro/Nano Current

“…The liquid supply rate was 20 µL/h. The moving collector provided a mechanical stretching effect on the viscous jet, and the jet deviated from the vertical line under the stretching force from the collector, making it difficult to obtain precise micro/nano patterns [25,26]; thus, the collector stopped at each turning point for 1.5 s. When the collector stopped, the jet whipped at the turning point position of the pattern, and more charges deposited on the collector in a short time, increasing the electrical interferences and resulting in the current peaks shown in Figure 2b. The peak current interval is an important value to characterize the repeatability of EDW current when printing patterned structures.…”

Microlens Fabrication by Replica Molding of Electro-Hydrodynamic Printing Liquid Mold

“…EHD printing is one of the most promising micro-nano additive manufacturing technologies with its unique advantages of low cost and high resolution [19][20][21]. It enables the direct, additive patterning of materials with a resolution that can extend below 100 nm, and can print drop on demand.…”