Papers by Keyword: Electrohydrodynamic

Abstract: Poly (3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS) is a conductive polymer and versatile material to fabricate numerous organic electronic devices. PEDOT:PSS inks were studied and analyzed for their sprayability via Electrohydrodynamic (EHD) printing. Commercially obtained pristine PEDOT:PSS ink could not produce any decent cone-jet mode due to its high surface tension and viscosity. Two different surfactants – acetone and ethanol were then dispersed into PEDOT:PSS at different concentrations to enhance the sprayability of the PEDOT:PSS ink. Both modified PEDOT:PSS inks could produce a cone-jet mode of spraying, which is essential for EHD printing. The flow rates were tested between 10 - 20 μl/hr. These limits were established to prevent the splashing effect at a higher flow rate (>20μl/hr) and inks disintegrating at a lower flow rate 5μl/hr. PEDOT:PSS:Acetone and PEDOT:PSS:Ethanol with 50:50 and 75:25 ratios, respectively, produced the best performance in their respective categories.

Abstract: The combination of electrohydrodynamic and wind forms a new kind of power generation mode. Strong electric field induction charged method makes water mist form electrofluid to offer ions, and air pump offers wind. The experimental phenomenon is tested by oscilloscope. The oscilloscope waveform records the effects of wind. The results show that the wind power generator unit can make wind force overcome electric field force to convert wind energy into electricity.

Abstract: In this paper is made an investigation of an ion-drag pump, using a needle-electrode configuration. Numerical calculations and modeling simulation are made for this electrohydrodynamic pump, with the mean to simulate, determine and analyze the liquid pressure, velocity and pump efficiency. The obtained results from simulation are compared with the results obtained by numerical calculations. An analysis of pump efficiency is made based on these results.

Abstract: EHD (Electrohydrodynamic) patterning forming micro structures with UV light curable materials at room temperature is investigated in this paper. It is a process for fabricating patterns on polymer film by applying electrical field to the template and the substrate as an electrode pair. The maintaining time of EHD patterning is reduced from several hours to tens of minutes by using UV curable polymer with low viscosity. The flat template generates the periodic pillars with micro scale. The periodic pillars with different period are obtained by varying the applied voltage in the different phase of experiment. The micro scale replication with good fidelity is produced by using patterned template made of doped silicon wafer.

Abstract: Electrohydrodynamic (EHD) has been applied in many areas, such as EHD atomization, EHD enhanced heat transfer, EHD pump, electrospray nanotechnology, etc. EHD atomization is a promising materials deposition technique as it allows uniform and regular deposition, and offers a range of other advantages, such as low cost compared with other current techniques, easy set-up, high deposition rate, and ambient temperature. Simulation is carried out using ANSYS FLUENT system. The approach in this work was to simultaneously solve the coupled (EHD) and electrostatic equations. The fields of velocities and pressure, as well as electric characteristics of EHD flows, are calculated. The model does not include a droplet break-up model.

Abstract: The effects of an ununiform electric field on bubble behaviours such as bubble growth ,deformation and detachment are investigated experimentally.Experimental results show that the bubble elongated along the direction of the electric field.The bubble’s aspect ratio is increased with the increasing of electric field intensity and the ellipse sphere shape is more evident than without electric field,while its departure volume is decreased with that.The case is the bubble comes under the electric stress.The electric stress compressed the bubble in the equatorial direction and extened the bubble along the axial direction.The bubble behaviours influenced in the ununiform electric field is more evident than the uniform electric field.

Abstract: Topography of the surface plays an important role in cellular responses. A novel method, called template-assisted electrohydrodynamic atomization (TAEA) spraying, was developed to create surface topography of hydroxyapatite (HA) on metallic surfaces. In this work, by varying the core process parameters (e.g. flow rate, applied voltage and distance between substrate and needle), the optimization and development of the TAEA process with nanoHA suspension is investigated with the aim of preparing a nanostructured HA coating with patterning of high resolution for biomedical applications.

Abstract: Bioceramic fibres, scaffolds and mats are important structures in biomedical applications. Electrohydrodynamic routes are relatively new for processing advanced materials and in this paper we use electrospinning to prepare zirconia fibres diameter down to 200nm and hydroxyapatite (HA) fibres down to 1$m. Zirconia-polymer and nHA-polymer composite scaffolds structures (mats) with 400-1000 $m windows were also prepared.