• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.217-217
• /
• 2006

The surface energy control capability of electrohydrodynamic force provides electrospraying with various potential advantages such as simple particle size control, mono-dispersity, high recovery, and mild processing conditions. Herein, the one step nano-encapsulation of protein drugs using electrospraying was developed. The major processing parameters such as the conductivity of spraying liquids, flow rate, the distance between electric potentials, etc were examined to obtain the maximum efficiency. The recovery of particles was found relatively high as could be conjectured based on the principle of electrospraying. When organic solvents were employed, the processing windows of electrospraying were relatively narrow than water systems. Efficient nano-encapsulation of BSA with polymers was conveniently achieved using electrospraying at above 12 kV.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.5
• /
• pp.126-133
• /
• 2015

Recently, there has been demand for polymeric porous membranes in various fields, such as environmental engineering, pharmaceutics, tissue engineering, drug delivery, biology, and fuel cells. In this study, it is proposed that a polymer particle-based porous membrane can be fabricated using electrospraying and sintering processes. Electrospraying can fabricate polymeric particles with diameters ranging from several micrometers to tens of nanometers without the cumbersome particle aggregation problem. Additionally, the particles can be sintered through thermo-compression under the glass transition temperature. In this study, a polymethyl methacrylate particle-based porous membrane with an average pore size of less than 500 nm is fabricated using the proposed method.

• Proceedings of the KSME Conference
• /
• 2005.11a
• /
• pp.179.1-179.1
• /
• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.331-332
• /
• 2012

• Polymer(Korea)
• /
• v.31 no.3
• /
• pp.215-220
• /
• 2007

The control of the surface energy by electrohydrodynamic force provides electrospraying with various potential advantages such as simple particle size control, mono-dispersity, high recovery, and mild processing conditions. The advantages are quite helpful to improve the stability of protein drug and control its release. Herein, the nano-encapsulation of protein drugs using electrospraying was investigated. Albumin as a model protein was processed using uniaxial and co-axial electrospraying, and chitosan, polycaporlactone (PCL), and poly (ethylene glycol) (PEG) were used as encapsulation materials. The major processing parameters such as the conductivity of spraying liquids, flow rate, the distance of electrical potential gradient, etc were measured to obtain the maximum efficiency. In the chitosan systems, mean particles size decreases as flow rate and the distance between nozzle and the collecting part decreases. In the uniaxial technique of the PCL systems, mean particles size decreases as flow rate decreases. In the coaxial technique of the PCL systems, it was found that the particles size gets larger under the application of the higher ratio of inner-to-outer liquid flow rates. The primary particles formed out of an electrospraying nozzle showed narrow particle size distribution, but once they arrived to the collecting part, aggregation behavior was observed obviously. Efficient nano-encapsulation of albumin with PCL, PEG, and chitosan was conveniently achieved using electrospraying at above 12 kV.

• Polymer(Korea)
• /
• v.35 no.3
• /
• pp.254-259
• /
• 2011

In electrospraying of polymer solutions, metal sample collectors are often ineffective in fully removing solvent from sprayed particles and recovering redispersable sprayed particles. Herein, a novel electro spraying system, where sprayed particles were dispersed into laminar flow of dispersant (coagulation liquid), was designed for the nano-encapsulation of protein drugs. Chitosan and polyacrylic acid were used as the encapsulation materials. Aggregation of particles could be prevented by using this new electrospraying system, and unimodal size distribution was observed at an applied voltage between 4~16 kV and a low flow rate. The effects of the applied voltage on mean particle size were not significant on the other hand.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2971-2976
• /
• 2007

The mode change from Taylor cone-jet to dripping in electrospraying has been analytically investigated. The change has been predicted by the dynamic behavior of a liquid drop at the tip of the cone-jet. Conservation laws are applied to determine the upward motion of the drop, and an instability model of electrified jets is used to determine the jet breakup. Finally, for the first time, the analysis enables prediction of the transition in terms of the Weber number and electric Bond number. The predictions are in good agreement with experimental data.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.1784-1788
• /
• 2014

The present study suggests a novel method to produce raspberry-like microparticles containing diverse functional materials inside. The raspberry-like microparticles were produced from a random assembly of uniformly-sized poly(methyl methacrylate) (PMMA) nanoparticles via electrospraying. The solution containing the PMMA nanoparticles were supplied through the inner nozzle and compressed air was emitted through the outer nozzle. The air supply helped fast evaporation of acetone, so it enabled copious amount of microparticles as dry powder. The microparticles were highly porous both on the surface and interiors, hence various materials with a function of UV-blocking ($TiO_2$ nanoparticles and methoxyphenyl triazine) or anti-aging (ethyl(4-(2,3-dihydro-1H-indene-5-carboxyamido) benzoate)) were loaded in large amount (17 wt % versus PMMA). The surface and interior structures of the microparticles were dependent on the characteristics of functional materials. The results clearly suggest that the process to prepare the raspberry-like microparticles can be an excellent approach to generate functional microstructures.

• Journal of Industrial and Engineering Chemistry
• /
• v.68
• /
• pp.416-424
• /
• 2018

Oil spill and oily wastewater have now become a serious threat to the freshwater and marine environments. Porous materials with super-hydrophobicity and super-oleophilicity are good candidates for the oil adsorption and oil/water separation. Here, flexible hybrid nanofibrous membrane (FHNM) containing $SiO_2$/polyvinylidene fluoride (PVDF) microspheres was prepared by simultaneous electrospinning and electrospraying. The obtained FHNM combined the flexibility of the nanofiber mat and super-hydrophobicity of the microspheres, which could not be achieved by either only electrospinning or only electrospraying. It was found that when the weight ratio between the $SiO_2$ and PVDF reached a critical value, the $SiO_2$ nanoparticles were present on the PVDF microsphere surface, significantly improving the surface roughness and hence the contact angle of the FHNM. Compared with the pure electrospun PVDF nanofiber mat, most of the FHNMs have a higher oil adsorption capacity. The FHNM could separate the oil with water quickly under the gravity and displayed a high efficiency and good reusability for the oil/water separation. More importantly, the FHNM could not only separate the oil with the pure water but also the corrosive solution including the salt, acid and alkali solution.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.12
• /
• pp.979-985
• /
• 2007

Spray combustion characteristics of the conducting fuel electrospray has been studied for clean combustion technology. The electrospraying multiplexed system which can maintain the characteristics of the cone-jet mode is able to obtain charged micro droplets with high flow rate. In addition, they have monodisperse distribution during operating the electrospray in the cone-jet mode. The multiplexed grooved nozzle system with the extractor was applied to this experimental device set up. The stable grooved mode can be generated by the grooved nozzle and this electrospray system was applied to the diffusion combustion. It is the first step to discover the diffusion combustion characteristics of the electrospray, In case of the single grooved nozzle electrospray the diffusion flames are occurred at each Jet of grooved mode and they are quite stable. The exhaust gas analysis was indicated that there is the critical point which can make very stable diffusion combustion