Phase field simulation of electrohydrodynamic jet droplets and printing microstructures on insulating substrates

Abstract

The phase field technique is a straightforward and effective mathematical model for resolving interfacial problems in E-Jet printing. The paper presents an exhaustive analysis for the Drop-on-demand electrohydrodynamic jet (DoD E-Jet) printing. The study introduces a phase field method to generate a stable cone jet morphology that can allow the production of micron/nano structures on different insulating substrates. Further, the impact of steel needle and quartz capillary were studied on the cone jet morphology for different insulating substrate. In trials, the optimal settings of flow rate and dc positive pulse voltage were adjusted to print drops for numerical simulation verification. However, a distinctive analysis of droplet formation on PET and glass substrates was demonstrated in order to lower droplet size and polarization of residual charges. The model is based on the Taylor–Melcher leaky dielectric model and employs the 2-phase field method to track the interface. The nozzle is capable of producing a magnificent micro-dripping jet and detaching stable drops from the substrate surface. As a result, the results are primarily concerned with droplet diameter and relative permittivity of ink. According to the simulation findings, microdroplets with a diameter of less than 100 μm are created on PET substrate with quick decay of residual charges, whereas drops with a diameter of less than 50 μm are formed on glass substrate. Furthermore, it is demonstrated in studies employing a nozzle with an internal diameter of 360 μm that is fixed to a quartz capillary with a diameter of 50 μm that it takes a significant amount of time, cost and effort. The approach can significantly guide printhead and parameter design for printing on insulating surfaces. It is a more convenient and efficient method for predicting pattern sizes with a small number of trials for MEMS device applications.