Advanced electrospinning using circle electrodes for freestanding PVDF nanofiber film fabrication

Kang, Dong Hee,Kang, Hyun Wook Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.455 No.-

<P><B>Abstract</B></P> <P>Here, we investigate a circle electrode in the electrospinning process for the fabrication of substrate-free, freestanding nanofiber films. Circle electrode-based electrospinning is controlled by varying the applied voltage and the metal needle tip-to-collector distance. The equipment used for the voltage source and syringe pump is the same as those in traditional electrospinning. A hollow cylinder is used as the circle electrode to ensure stable electrostatic conditions on the top surface of the cylinder collector. Many studies of electrospinning have presented parameters for optimal film fabrication that are inadequate for film fabrication on wire electrode-based electrospinning. To overcome obstacles inherent to substrate-free film fabrication, the voltage and tip-to-collector distance are controlled in the circle electrode-based electrospinning process. Numerical simulation is used to determine the electric field in the electrospinning process for quantitative analysis. Under voltages of 6–18 kV and tip-to-collector distances of 30–100 mm, a freestanding film is successfully fabricated on a circle electrode with 20-mm inner diameter. The freestanding electrospun film can be transferred as a coating to a non-planar surface without using additional processes. Thus, the electrospinning process using the circle electrode collector was successfully optimized for freestanding film fabrication. Substrate-free electrospun films can be applied to multifunctional filters for dust filtration with humidity blocking. Regarding future applications, the circle electrode-based electrospinning process verified the potential for integrating freestanding electrospun films into organs-on-chip, biochemical sensors, and microfluidic analysis systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Freestanding nanofiber film collected using a circle electrode collector. </LI> <LI> Easy transfer process of freestanding nanofiber film onto a non-planar surface. </LI> <LI> Numerical studies were performed to investigate an electric field during electrospinning. </LI> <LI> High productivity and uniform nanofiber film fabrication process. </LI> <LI> Application to multifunctional filter for dust filtration and humidity blocking. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

An investigation on quilled nozzle-less electrospinning in comparison with conventional methods for producing PAN nanofibers

Sayed Pedram Rezazadeh Tehrani,Mehdi Hadjianfar,Mehran Afrashi,Dariush Semnani 한국의류학회 2018 Fashion and Textiles Vol.5 No.1

Over the last decades by appearing nanotechnology electrospinning has been reconsidered as a significant method. However, electrospinning production rate is limited by the rate at which the polymer solution or melt is fed to a single jet. Feeding rate can be increased through implementing a wide range of methods such as multiple nozzle electrospinning. In the present work, an innovative “quilled” drum with a peculiar design was rotated in a PAN polymer solution in an electrical field to optimize energy consumption, uniform nanofiber distribution on the collector, and increase production rate. The produced nanofibers were compared with those produced from modified multi-nozzle and single-nozzle electrospinning methods. The mean diameters of nanofibers produced from the quilled drum was 32% greater than that of single-nozzle and 28% less than multi-nozzle electrospinning. The CV% of thickness of the webs were 7.9, 11.2, and 12.5% for the quilled, single nozzle and multi-nozzle methods, respectively which showed the presented method produced more uniform webs. The production rate of this electrospinning was 60 and 17 times more than single and multi-nozzle methods, respectively.

용융전기방사에 의한 마이크로섬유 제작과 적층 구조의 특성 평가

신광준(Gwang June Shin),정영훈(Young Hun Jeong) 한국가시화정보학회 2016 한국가시화정보학회 학술발표대회 논문집 Vol.2016 No.12

Melt-electrospinning, which is one kind of advanced manufacturing processes, has gotten more attention nowadays. Its characteristics include 2 areas which called fused deposition modeling and electrospinning. And also we can fabricate tissue engineering’s scaffolds by these theories. Melt-electrospinning can generate filaments in micrometer-level, meanwhile, the manufacturing condition, which can influent filaments’ diameter, is easy to control. On another hand, melt-electrospinning also can builds layers up easily and more safety than electrospinning which uses solvent for dissolving polymers. In this study, melt-electrospinning is used to fabricate microfibrous nonwoven structure with stiffness. With the various pitch conditions, it was demonstrated that characteristics of the fabricating microfibrous structures can be successfully controlled.

전기방사 거동의 정밀제어를 위한 전기방사 불안정성에 관한 기초적 연구

예나경,김한성,Ye, Nakyung,Kim, Hanseong 한국섬유공학회 2012 한국섬유공학회지 Vol.49 No.4

In this study, the instabilities of electrospinning were observed and evaluated by measuring the drop area, the current, and the electrical force using PVAc and PVA. Those values were measured simultaneously during electrospinning and the instabilities were analyzed as a function of time. The electrospinning was carried out by changing the voltages and the feed rates. The results suggest that different electrospinning conditions such as voltage, polymer, and flow rate caused different behaviors of instabilities, current and electric force, however, all the used methods were effective for studying the instabilities in electrospinning.

Surface energy characteristics of zeolite embedded PVDF nanofiber films with electrospinning process

Kang, D.H.,Kang, H.W. New York] ; North-Holland 2016 APPLIED SURFACE SCIENCE - Vol.387 No.-

Electrospinning is a nano-scale fiber production method with various polymer materials. This technique allows simple fiber diameters control by changing the physical conditions such as applied voltage and polymer solution viscosity during the fabrication process. The electrospun polymer fibers form a thin porous film with high surface area to volume ratio. Due to these unique characteristics, it is widely used for many application fields such as photocatalyst, electric sensor, and antibacterial scaffold for tissue engineering. Filtration is one of the main applications of electrospun polymer fibers for specific application of filtering out dust particles and dehumidification. Most polymers which are commonly used in electrospinning are hard to perform the filtering and dehumidification simultaneously because of their low hygroscopic property. To overcome this obstacle, the desiccant polymers are developed such as polyacrylic acid and polysulfobetaine methacrylate. However, the desiccant polymers are generally expensive and need special solvent for electrospinning. An alternating way to solve these problems is mixing desiccant material like zeolite in polymer solution during an electrospinning process. In this study, the free surface energy characteristics of electrospun polyvinylidene fluoride (PVDF) film with various zeolite concentrations are investigated to control the hygroscopic property of general polymers. Fundamental physical property of wettability with PVDF shows hydrophobicity. The electrospun PVDF film with small weight ratio with higher than 0.1% of zeolite powder shows diminished contact angles that certifying the wettability of PVDF can be controlled using desiccant material in electrospinning process. To quantify the surface energy of electrospun PVDF films, sessile water droplets are introduced on the electrospun PVDF film surface and the contact angles are measured. The contact angles of PVDF film are 140<SUP>o</SUP> for without zeolite and 80<SUP>o</SUP> for with 5wt% of zeolite respectively. As a result, the surface energy of PVDF film can be controlled by embedding zeolite particles in electrospinning process and applied to filtration application of dust filtering and dehumidification simultaneously with low manufacturing cost.

Syringeless electrospinning toward mass-production of nanofibers and their applications

문성준,이경진 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

Electrospinning has been attracted by many researchers because it is very generic to fabricate nanofiber with easy diameter control. Despite of attractive advantages, the electrospinning couldn`t use in practical fields due to its low productivity. We think that these issues are attributed to the syringe-based system. Here, we introduce syringeless electrospinning system toward mass-production of nanofiber using helical probed rotating cylinder. Conductive probes were impregnated on the rotating cylinder with DC voltage supplier to easily draw polymeric solution and generate a Taylor cone. The modified rotating cylinder provide the batch-based-continuous system, which can make the electrospinning easier than previous technique. As the result, the amount of nanofibers were increased fivefold than the previous electrospinning. Furthermore the method can be applied to applications such as colloidal electrospinning and multi-layered mass production.

Magnetic-Field-Assisted Emulsion Electrospinning System: Designing, Assembly, and Testing for the Production of PCL/Gelatin Core–Shell Nanofibers

Fatemeh Kashani‑Asadi‑Jafari,Ahmadreza Parhizgar,Afra Hadjizadeh 한국섬유공학회 2023 Fibers and polymers Vol.24 No.2

There are different methods for producing core–shell nanofibers, one of which is the emulsion electrospinning method. Thestability of the emulsion during electrospinning is one of the most critical factors in the quality of the fibers. In this study, amagnetic-field-assisted emulsion electrospinning system was designed, built, and tested to keep the emulsion stable withoutadditives or sonication. Polycaprolactone (PCL) 10 wt. % in dichloromethane (DCM) for the shell and gelatin 2.5 wt. % inwater for the core was used. Scanning electron microscope (SEM) image of samples with different weight ratios of componentsboth with and without using the magnetic-field-assisted emulsion electrospinning system at different rotational speedswas investigated. Transition electron microscope (TEM) images of the sample with a ratio of 1/10 (gel/PCL) at differentrotational speeds were studied. The fibers were finally analyzed by Fourier transform infrared (FTIR) and tensile strengthmachine. According to the results, there was no change in the bonds in the materials after electrospinning. The designedsystem improved the fiber texture and reduced its structural problems significantly. By increasing the rotation speed of themagnet from 700 to 900 rpm, an improvement in fiber morphology and uniformity in diameter was observed. The compositionof gelatin/PCL with a ratio of 1/10 was selected as the optimal condition. The spun nanofibers in these conditionshad a uniform structure without the bead, and the presence of both polymers uniformly in the fibers was shown. Finally,the magnetic-field-assisted emulsion electrospinning system successfully held the emulsion stable during electrospinningwithout additives.

Novel robot-assisted angled multi-nozzle electrospinning set-up: computer simulation with experimental observation of electric field and fiber morphology

Park, Chan Hee,Pant, Hem Raj,Kim, Cheol Sang Sage Science Press 2014 Textile Research Journal Vol. No.

<P>The development of a unique multi-nozzle electrospinning set-up and the study of the effect of an electric field on different types of spinneret are of major concern for broadening the industrial application of electrospinning. In the present paper we describe a novel robot-assisted angled multi-nozzle electrospinning set-up for the mass production of nanofibers and compare the computer simulation and the experimental results for the measurement of the electric field and fiber morphology. Three nozzle configurations, with a 90°, 100°, or 180° angle between the nozzles, and two operating conditions of the nozzle holder (fixed and movable), were studied to observe the electric field strength and its effect on fiber diameter. The results of the electrospinning experiments and electric field simulation demonstrated that the interference of the electric field was greatest with the 90° configuration and the nozzle holder held in a fixed position, whereas when the nozzle holder was movable it was greatest at 180°. The study was carried out using either two or eight nozzles, and the results showed that the electric field remained the same for a given configuration of the nozzle holder and the configuration angle, regardless of the number of nozzles. The study also showed that by controlling the movable nozzle holder and its angle the fiber diameter could be regulated without changing other material or processing parameters.</P>

Two-nozzle electrospinning of (MWNT/PU)/PU nanofibrous composite mat with improved mechanical and thermal properties

Leonard D. Tijing,Woorim Choi,Zhe Jiang,Altangerel Amarjargal,Chan-Hee Park,Hem Raj Pant,Ik-Tae Im,김철생 한국물리학회 2013 Current Applied Physics Vol.13 No.7

Composite nanofibrous mat composed of neat polyurethane (PU) and multiwalled carbon nanotubes/polyurethane (MWNT/PU) nanofibers have been fabricated by one-step angled two-nozzle electrospinning. The morphological, thermal, and mechanical properties of the electrospun nanofibers were evaluated. The diameters of electrospun neat PU and composite nanofibers ranged from 239 to 1058 nm. The two-nozzle electrospun (MWNT/PU)/PU composite nanofibers showed curly, and randomly-oriented fibers with interfiber bonding, and were generally bigger in size than single-nozzle electrospun nanofibers. The tensile strength of the neat PU composite nanofiber mat obtained from two-nozzle electrospinning was 25% higher than that obtained from neat PU single-nozzle electrospinning. The incorporation of MWNTs in the composite nanofiber increased the tensile strength by as much as 64%without reducing elongation, made the composite nanofiber more thermally stable, and improved the melting zone. The present results showed that side-by-side angled two-nozzle electrospinning can improve the quality of the electrospun nanofibers that could have potential application in different fields such as filtration, protective clothing and tissue engineering.

Nanofibers from electrically driven viscoelastic jets: modeling and experiments

Carroll, Colman P.,Zhmayev, Eduard,Kalra, Vibha,Joo, Yong-Lak The Korean Society of Rheology 2008 Korea-Australia rheology journal Vol.20 No.3

Modeling and experiments of three electrospinning systems have been presented and they are i) axisymmetric instabilities in electrospinning of various polymeric solutions, ii) non-isothermal modeling of polymer melt electrospinning, and iii) control of nanoparticle distribution and location via confined self-assembly of block copolymers during electrospinning. It has been demonstrated that predicted simulations are in good agreement with corresponding electro spinning experiments, and theoretical analysis provides fundamental understanding of phenomena that take place during electrospinning of various polymeric liquids.