Deposition of Bead Arrays With Variable Diameter by Self-Focusing of Electrohydrodynamic Jets

2017 ◽  
Author(s):  
Nicolas Martinez-Prieto ◽  
Gabriela Fratta ◽  
Jian Cao ◽  
Kornel Ehmann
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Deposition Process ◽  
Direct Writing ◽  
Variable Diameter ◽  
Self Focusing ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Number Of Passes ◽  
Bead Arrays

Electrohydrodynamic processes were used for direct-writing of bead arrays with controllable bead sizes. Experiments were conducted to align layers of bead-on-string structures in an effort to create three-dimensional patterns. The results show that the jet focuses on previously deposited droplets allowing for the selective deposition of material over already deposited patterns. Jet attraction to already deposited solutions on the substrate is attributed to the charge transport at the liquid ink-metal collector interface and the dielectric properties of the water/poly(ethylene oxide) solution under an electric field. The deposition process consists of 3 steps: (1) deposition of a layer of bead-on-string structures, (2) addition of extra volume to the beads by subsequent passes of the jet, and (3) evaporation of the solvent resulting in an array of beads with varying sizes. Patterns with up to 20 passes were experimentally obtained. The beads’ height was seen to be independent of the number of passes. The process reported is a simple, fast, and low-cost method for deposition of bead arrays with varying diameters.

Deposition of Variable Bead Diameter Arrays by Self-Focusing Electrohydrodynamic Jets

2018 ◽  
Vol 6 (3) ◽  
Author(s):  
Nicolas Martinez-Prieto ◽  
Gabriela Fratta ◽  
Jian Cao ◽  
Kornel F. Ehmann
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Deposition Process ◽  
Direct Writing ◽  
Self Focusing ◽  
Poly Ethylene Oxide ◽  
Bead Diameter ◽  
Poly Ethylene ◽  
Number Of Passes ◽  
Bead Arrays

Electrohydrodynamic (EHD) processes were used for direct writing of bead arrays with controllable bead sizes. Experiments were conducted to align layers of bead-on-string structures in an effort to create three-dimensional patterns. The results show that the jet focuses on previously deposited droplets allowing for the selective deposition of material over already deposited patterns. Jet attraction to already deposited solutions on the substrate is attributed to the charge transport at the liquid ink–metal collector interface and the dielectric properties of the water/poly(ethylene oxide) (PEO) solution under an electric field. The deposition process consists of three steps: (1) deposition of a layer of bead-on-string structures, (2) addition of extra volume to the beads by subsequent passes of the jet, and (3) evaporation of the solvent resulting in an array of beads with varying sizes. Patterns with up to 20 passes were experimentally obtained. The beads' height was seen to be independent of the number of passes. The process reported is a simple, fast, and low-cost method for deposition of bead arrays with varying diameters.

scholarly journals Design and Optimization of Piezoresistive PEO/PEDOT:PSS Electrospun Nanofibers for Wearable Flex Sensors

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2166
Author(s):  
Eve Verpoorten ◽  
Giulia Massaglia ◽  
Gianluca Ciardelli ◽  
Candido Fabrizio Pirri ◽  
Marzia Quaglio
Keyword(s):  
Low Cost ◽  
Electrospun Nanofibers ◽  
Strain Sensors ◽  
Active Materials ◽  
Design And Optimization ◽  
Piezoelectric Strain ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Poly Styrene Sulfonate ◽  
Flex Sensors

Flexible strain sensors are fundamental devices for application in human body monitoring in areas ranging from health care to soft robotics. Stretchable piezoelectric strain sensors received an ever-increasing interest to design novel, robust and low-cost sensing units for these sensors, with intrinsically conductive polymers (ICPs) as leading materials. We investigated a sensitive element based on crosslinked electrospun nanofibers (NFs) directly collected and thermal treated on a flexible and biocompatible substrate of polydimethylsiloxane (PDMS). The nanostructured active layer based on a blend of poly(ethylene oxide) (PEO) and poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) as the ICP was optimized, especially in terms of the thermal treatment that promotes electrical conductivity through crosslinking of PEO and PSS, preserving the nanostructuration and optimizing the coupling between the sensitive layer and the substrate. We demonstrate that excellent properties can be obtained thanks to the nanostructured active materials. We analyzed the piezoresistive response of the sensor in both compression and traction modes, obtaining an increase in the electrical resistance up to 90%. The Gauge Factors (GFs) reflected the extraordinary piezoresistive behavior observed: 45.84 in traction and 208.55 in compression mode, which is much higher than the results presented in the literature for non-nanostructurated PEDOT.

Material Systems Used by Micro Dispensing and Ink Jetting Technologies

2000 ◽  
Vol 624 ◽  
Author(s):  
Jie Zhang ◽  
Irina Shmagin ◽  
James Skinner ◽  
John Szczech ◽  
Daniel Gamota
Keyword(s):  
Transmission Lines ◽  
Flexible Manufacturing ◽  
Low Cost ◽  
High Volume ◽  
Deposition Process ◽  
Electrical Performance ◽  
Direct Writing ◽  
Environmental Conditioning ◽  
Process Characterization ◽  
Material Systems

ABSTRACTIn today's electronic industry, manufacturers are continuously improving capital utilization, developing flexible manufacturing processes, reduce changeover time and improving yield and throughput. Interest in rapid prototyping and 3-D fabrication capabilities are rapidly increasing, and a number of candidate direct writing technologies are in development to meet these demands.This work studies material systems used by data driven materials deposition (DDMD) technologies for potential low temperature reel-to-reel high volume manufacturing on low cost substrates. Characterization results of fabricated discrete and RF devices using commercially available micro dispensing and ink jet systems will be discussed. Material rheological properties, deposition process characterization, deposition repeatability, fabricated device reliability and electrical performance will be presented. The test vehicles contain resistors and capacitors, transmission lines, open and short series stub filters, and half-wavelength resonators. The material/substrate compatibility will be demonstrated through environmental conditioning of the test vehicles. In addition, a cost estimate for using micro dispensing technologies was conducted to compare current manufacturing technologies to DDMD.

Study of Microscale Three-Dimensional Printing Using Near-Field Melt Electrospinning

2017 ◽  
Author(s):  
Xiangyu You ◽  
Chengcong Ye ◽  
Ping Guo
Keyword(s):  
High Resolution ◽  
3D Printing ◽  
Low Cost ◽  
Near Field ◽  
Three Dimensional ◽  
Thin Wall ◽  
Direct Writing ◽  
Melt Electrospinning ◽  
Wall Structures ◽  
Jet Trajectory

Three-dimensional (3D) printing of microscale structures with high resolution (sub-micron) and low cost is still a challenging work for the existing 3D printing techniques. Here we report a direct writing process via near-field melt electrospinning to achieve microscale printing of single filament wall structures. The process allows continuous direct writing due to the linear and stable jet trajectory in the electric near-field. The layer-by-later stacking of fibers, or self-assembly effect, is attributed to the attraction force from the molten deposited fibers and accumulated negative charges. We demonstrated successful printing of various 3D thin wall structures (freestanding single walls, double walls, annular walls, star-shaped structures, and curved wall structures) with a minimal wall thickness less than 5 μm. By optimizing the process parameters of near-field melt electrospinning (electric field strength, collector moving speed, and needle-to-collector distance), ultrafine poly (ε-caprolactone) (PCL) fibers have been stably generated and precisely stacked and fused into 3D thin-wall structures with an aspect ratio of more than 60. It is envisioned that the near-field melt electrospinning can be transformed into a viable high-resolution and low-cost microscale 3D printing technology.

scholarly journals Monolith formation and ring-stain suppression in low-pressure evaporation of poly(ethylene oxide) droplets

2012 ◽  
Vol 695 ◽  
pp. 321-329 ◽  
Author(s):  
Kyle A. Baldwin ◽  
Samuel Roest ◽  
David J. Fairhurst ◽  
Khellil Sefiane ◽  
Martin E. R. Shanahan
Keyword(s):  
Ethylene Oxide ◽  
Triple Line ◽  
Deposition Process ◽  
Low Pressure ◽  
Quantitative Model ◽  
Dimensionless Number ◽  
Coffee Ring ◽  
Wide Range ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

AbstractWhen droplets of dilute suspensions are left to evaporate the final dry residue is typically the familiar coffee-ring stain, with nearly all material deposited at the initial triple line (Deegan et al., Nature, vol. 389, 1997, pp. 827–829). However, aqueous poly(ethylene oxide) (PEO) droplets only form coffee-ring stains for a very narrow range of the experimental parameters molecular weight, concentration and drying rate. Instead, over a wide range of values they form either a flat disk or a very distinctive tall central monolith via a four-stage deposition process which includes a remarkable bootstrap-building step. To predict which deposit will form, we present a quantitative model comparing the effects of advective build-up at the triple line to diffusive flux and use this to calculate a dimensionless number $\chi $. By experimentally varying concentration and flux (using a low-pressure drying chamber), the prediction is tested over nearly two orders of magnitude in both variables and shown to be in good agreement with the boundary between disks and monoliths at $\chi \approx 1. 6$.

scholarly journals Production of Prednisolone byPseudomonas oleovoransCells Incorporated Into PVP/PEO Radiation Crosslinked Hydrogels

2004 ◽  
Vol 2004 (4) ◽  
pp. 219-226 ◽  
Author(s):  
Abeer Abd El-Hady ◽  
Hassan A. Abd El-Rehim
Keyword(s):  
Substrate Concentration ◽  
Three Dimensional ◽  
Vinyl Pyrrolidone ◽  
Pseudomonas Oleovorans ◽  
Factors Affecting ◽  
Dimensional Network ◽  
Concentration Maximum ◽  
Poly Ethylene Oxide ◽  
Repeated Use ◽  
Poly Ethylene

In order to rise the yield of prednisolone from hydrocortisone, thePseudomonas oleovoranscells were entrapped into radiation crosslinked poly(vinyl pyrrolidone)/poly(ethylene oxide)(PVP/PEO) hydrogel of different gel contents. The factors affecting the gel content and swelling behavior of the polymeric gel, such aspolymercomposition,polymerblend concentration, and irradiation doses, were investigated. The formation of gels having a good strength with the ability to retain a desirable amount of water in their three-dimensional network can be achieved by using PVP/PEO copolymer of composition(90:10)and concentration of 15% prepared at 20 kGy irradiation dose. At these conditions the prepared hydrogel is considered the most favorable one that gave the highest hydrocortisone bioconversion and prednisolone yield, 81% and 62.8%, respectively. The improvement of prednisolone yield was also achieved by increasing substrate concentration. Maximum hydrocortisone bioconversion (86.44) was obtained at 18 hours by using substrate concentration of 30 mg. Reusability of immobilizedPseudomonas oleovoransentrapped into PVP/PEO copolymer hydrogel was studied. The results indicated that the transformation capacity of hydrocortisone to prednisolone highly increased by the repeated use of copolymer for 4 times. This was accompanied by an increase in prednisolone yield to 89% and the bioconversion of hydrocortisone was 98.8%.

Study of Microscale Three-Dimensional Printing Using Near-Field Melt Electrospinning

2017 ◽  
Vol 5 (4) ◽  
Author(s):  
Xiangyu You ◽  
Chengcong Ye ◽  
Ping Guo
Keyword(s):  
High Resolution ◽  
3D Printing ◽  
Low Cost ◽  
Near Field ◽  
Three Dimensional ◽  
Thin Wall ◽  
Direct Writing ◽  
Melt Electrospinning ◽  
Wall Structures ◽  
Jet Trajectory

Three-dimensional (3D) printing of microscale structures with high-resolution (submicron) and low-cost is still a challenging work for the existing 3D printing techniques. Here, we report a direct writing process via near-field melt electrospinning (NFME) to achieve microscale printing of single filament wall structures. The process allows continuous direct writing due to the linear and stable jet trajectory in the electric near field. The layer-by-layer stacking of fibers, or self-assembly effect, is attributed to the attraction force from the molten deposited fibers and accumulated negative charges. We demonstrated successful printing of various 3D thin-wall structures with a minimal wall thickness less than 5 μm. By optimizing the process parameters of NFME, ultrafine poly (ε-caprolactone) (PCL) fibers have been stably generated and precisely stacked and fused into 3D thin-wall structures with an aspect ratio of more than 60. It is envisioned that the NFME can be transformed into a viable high-resolution and low-cost microscale 3D printing technology.

Fabrication of Three-Dimensional Porous Keratin/PEO Biological Scaffolds

2013 ◽  
Vol 821-822 ◽  
pp. 1035-1038
Author(s):  
Jia Li ◽  
Li Hua Yu ◽  
Jie Fan ◽  
Yong Liu
Keyword(s):  
Sodium Dodecyl ◽  
Three Dimensional ◽  
Cold Trap ◽  
Freezing Process ◽  
Optimum Process ◽  
Drying Process ◽  
Biological Scaffolds ◽  
Molecular Weight Cutoff ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

In order to prepare the keratin biological scaffold, keratin was firstly extracted from human hair by immersing in 200mL of aqueous solution containing 7mol/L urea, 2wt% Sodium dodecyl sulfate (SDS), and 5wt% sodium disulfite (Na2S2O6). The mixture was then heated to 95°C, shaking for 4h, and filtered through a stainless-steel mesh, dialyzed against 3L of distilled water, with cellulose tubing having a molecular weight cutoff of 10000~14000Da for 36h and filtered again. To examine the property of keratin scaffold, the vacuum freeze-drying process of pure keratin was investigated to find the optimum process. In order to further improve the property of keratin scaffold, different contents of Poly Ethylene Oxide (PEO) were added into the keratin solution. The result showed that the optimum freezing process was that Freezing at room temperature for 4h, and then put the sample into the refrigerator from ambient temperature to-20°C for 4h. Then the sample was put into the cold trap for 24h at-56°C. During the last 4 hours, the vacuum pump was opened and the frozen temperature was raised gradually. The keratin scaffold with good mechanical properties and uniform porosity was fabricated when the concentration of keratin solution was 10wt%. Additionally, PEO plays an important role in improving the flexibility of keratin/PEO scaffold.

Ultra-Low-Cost and Flexible Paper-Based Microplasma Generation Devices for Maskless Patterning of Poly(ethylene oxide)-like Films

2014 ◽  
Vol 6 (15) ◽  
pp. 12550-12555 ◽  
Author(s):  
Yao-Jhen Yang ◽  
Meng-Yu Tsai ◽  
Wei-Chieh Liang ◽  
Hsien-Yeh Chen ◽  
Cheng-Che Hsu
Keyword(s):  
Ethylene Oxide ◽  
Low Cost ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Maskless Patterning
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