The authors would like to acknowledge Mr. Dwight D. Barry for his important contributions for fabrication of the solution blow spinning apparatus. Zois Tsinas and Ran Tao would like to acknowledge funding from the National Institute of Standards and Technology under Awards # 70NANB20H007 and # 70NANB15H112, respectively.

NOTE: Details related to the equipment, instrumentation, and chemicals used in this section can be found in the Table of Materials. This entire protocol should first be reviewed and approved by the institutional safety department/personnel to ensure procedures and processes specific to the institution are adhered to.
1. Preparation of polymer solution using the appropriate solvent
NOTE: Consult manufacturer/supplier safety data sheets and the institut...

<ol>
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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexible+multi-layered+armor.">Flexible multi-layered armor.</a> Patent No. WO/1989. , (1989).</li><li>Cena, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BSCCO+superconductor+micro/nanofibers+produced+by+solution+blow-spinning+technique.">BSCCO superconductor micro/nanofibers produced by solution blow-spinning technique.</a> Ceramics International. 43 (10), 7663-7667 (2017).</li><li>Miller, C. L., Stafford, G., Sigmon, N., Gilmore, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conductive+nonwoven+carbon+nanotube-PLA+composite+nanofibers+towards+wound+sensors+via+solution+blow+spinning.">Conductive nonwoven carbon nanotube-PLA composite nanofibers towards wound sensors via solution blow spinning.</a> IEEE Transactions on Nanobioscience. 18 (2), 244-247 (2019).</li><li>Iorio, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conformational+changes+on+PMMA+induced+by+the+presence+of+TiO+2+nanoparticles+and+the+processing+by+Solution+Blow+Spinning.">Conformational changes on PMMA induced by the presence of TiO 2 nanoparticles and the processing by Solution Blow Spinning.</a> Colloid and Polymer Science. 296 (3), 461-469 (2018).</li><li>Mart&#237;nez-Sanz, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antimicrobial+poly+(lactic+acid)-based+nanofibres+developed+by+solution+blow+spinning.">Antimicrobial poly (lactic acid)-based nanofibres developed by solution blow spinning.</a> Journal of Nanoscience and Nanotechnology. 15 (1), 616-627 (2015).</li><li>Wang, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+flexible+indium+tin+oxide+nanofiber+transparent+electrodes+by+blow+spinning.">Highly flexible indium tin oxide nanofiber transparent electrodes by blow spinning.</a> ACS Applied Materials and Interfaces. 8 (48), 32661-32666 (2016).</li><li>Greenhalgh, R. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybrid+sol-gel+inorganic/gelatin+porous+fibres+via+solution+blow+spinning.">Hybrid sol-gel inorganic/gelatin porous fibres via solution blow spinning.</a> Journal of Materials Science. 52 (15), 9066-9081 (2017).</li><li>Gonzalez-Abrego, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesoporous+titania+nanofibers+by+solution+blow+spinning.">Mesoporous titania nanofibers by solution blow spinning.</a> Journal of Sol-Gel Science and Technology. 81 (2), 468-474 (2017).</li><li>Oliveira, J. E., Zucolotto, V., Mattoso, L. H., Medeiros, E. 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L., Behrens, A. M., Sandler, A. D., Kofinas, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+the+fundamental+principles+and+applications+of+solution+blow+spinning.">A review of the fundamental principles and applications of solution blow spinning.</a> ACS Applied Materials and Interfaces. 8 (51), 34951-34963 (2016).</li><li>Hofmann, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+nozzle+device+for+ultrafine+fiber+solution+blow+spinning+with+precise+diameter+control.">Microfluidic nozzle device for ultrafine fiber solution blow spinning with precise diameter control.</a> Lab on a Chip. 18 (15), 2225-2234 (2018).</li><li>Behrens, A. 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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Principles of polymer chemistry. , (1953).</li><li>Palangetic, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dispersity+and+spinnability:+Why+highly+polydisperse+polymer+solutions+are+desirable+for+electrospinning.">Dispersity and spinnability: Why highly polydisperse polymer solutions are desirable for electrospinning.</a> Polymer. 55 (19), 4920-4931 (2014).</li><li>Ying, Q., Chu, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overlap+concentration+of+macromolecules+in+solution.">Overlap concentration of macromolecules in solution.</a> Macromolecules. 20 (2), 362-366 (1987).</li><li>Haro-P&#233;rez, C., Andablo-Reyes, E., D&#237;az-Leyva, P., Arauz-Lara, J. 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The full description of the procedures used in this paper requires the identification of certain commercial products and their suppliers. The inclusion of such information should in no way be construed as indicating that such products or suppliers are endorsed by NIST or are recommended by NIST or that they are necessarily the best materials, instruments, software or suppliers for the purposes described.

The method described herein provides a protocol for producing polymer elastomer nanocomposite fiber mats via a relatively new technique known as solution blow spinning. This technique allows the fabrication of fibers in the nanoscale and has several advantages over other well-established techniques, such as the electrospinning process, as it can be carried out under atmospheric pressure and room temperature27. Furthermore, SBS is not highly susceptible to local environmental changes (temperature o...

Many light-weight, ballistic, protective armor systems are currently constructed using high-modulus and high-strength polymeric fibers, such as oriented, ultra-high molar mass polyethylene fibers or aramids, which provide outstanding ballistic resistance1,2. These fibers are used in combination with an elastic resin material (binder) that can penetrate to the filament level and secure the fibers in a 0&#176;/90&#176; configuration to form a non-woven, unidirectional laminate. The percentage of the polymer elastomer resin (binder) should not exceed 13% of the total weight of the unidirectional laminate to maintain the structural integrity and antiballistic properties of the laminate structure3,4. The binder is a very important component of the armor as it keeps the high-strength fibers properly oriented and tightly packed within each laminate layer3. Elastomer materials commonly used as binders in body armor applications have very low tensile modulus (e.g., ~17.2 MPa at ~23 &#176;C), low glass transition temperature (preferably below -50 &#176;C), very high elongation at break (as high as 300%) and must demonstrate excellent adhesive properties5.
To improve the performance of these polymer elastomers, SBS was performed to create fibrous elastomer materials that can be used as binders in body armor applications. SBS is a relatively new, versatile technique allowing the use of different polymer/solvent systems and the creation of different end products6,7,8,9,10,11,12,13. This simple process involves the rapid (10x the rate of electrospinning) deposition of conformal fibers onto both planar and nonplanar substrates to fabricate sheets or webs of fibers that encompass&#160;nano and micro length scales14,15,16,17,18. SBS materials have numerous applications in medical products, air filters, protective equipment, sensors, optical electronics, and catalysts14,19,20. Developing small diameter fibers can drastically increase the surface area to volume ratio, which is very important for several applications, especially in the personal protective equipment field. The diameter and morphology of the fibers generated by SBS depend&#160;on the molar mass of the polymer, polymer concentration in the solution, viscosity of the solution, polymer solution flow rate, gas pressure, working distance, and diameter of the spray nozzle14,15,17.
An important characteristic of the SBS apparatus is the spray nozzle consisting of an inner and a concentric outer nozzle. The polymer dissolved in a volatile solvent is pumped through the inner nozzle while a pressurized gas flows through the outer nozzle. The high-velocity gas exiting the outer nozzle induces shearing of the polymer solution flowing through the inner nozzle. This forces the solution to form a conical shape when exiting the spray nozzle. When the surface tension at the tip of the cone is overcome, a fine stream of polymer solution is ejected, and the solvent rapidly evaporates causing polymer strands to coalesce and deposit as polymer fibers. The formation of a fibrous structure, as solvent evaporates, strongly depends on the polymer molar mass and the solution concentration. Fibers are formed by chain entanglement, when polymer chains in solution begin to overlap at a concentration known as the critical overlap concentration (c*). Therefore, it is necessary to work with polymer solutions above the c* of the polymer/solvent system selected. Also, an easy strategy to attain this is to choose polymers with relatively high molar mass. Polymers with higher molar mass have increased polymer relaxation times, which is directly related to an increase in the formation of fibrous structures, as described in the literature21. As many of the parameters used in SBS are strongly correlated, the goal of this work is to provide guidance to develop tunable, and flexible polymeric fiber nanocomposites to be used as alternatives for typical binder materials found in body armor applications by incorporating nanoparticles in the fibrous polymer-elastomer matrix.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>45 MM Toolmaker Vise</td>
			<td>Tormach Inc.</td>
			<td>32547</td>
			<td>To secure substrate onto the collector</td>
		</tr>
		<tr>
			<td>ARES-G2 Rheometer</td>
			<td>TA Instruments</td>
			<td>401000.501</td>
			<td>Rheometer</td>
		</tr>
		<tr>
			<td>Branson Ultrasonics M Series - Ultrasonic Cleaning Bath</td>
			<td>Fisher Scientific</td>
			<td>15-336-100</td>
			<td>To disperse nanoparticles</td>
		</tr>
		<tr>
			<td>Cadence Science&#160;Micro-Mate Interchangeable Syringe</td>
			<td>Fisher Scientific</td>
			<td>14-825-2A</td>
			<td>Glass Syringe 5mL in 1/5mL, Luer Lock Tip</td>
		</tr>
		<tr>
			<td>Chemical hood</td>
			<td>Any company</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Corning - Disposable Pasteur Glass Pipette</td>
			<td>Sigma Aldrich</td>
			<td>CLS7095D5X-200EA</td>
			<td>Non-Sterile</td>
		</tr>
		<tr>
			<td>DWK Life Sciences&#160;Wheaton - Glass Scintillation Vial</td>
			<td>Fisher Scientific</td>
			<td>03-341-25G</td>
			<td>20 mL with cap</td>
		</tr>
		<tr>
			<td>FEI Quanta 200 Scanning Electron Microscope (SEM)</td>
			<td>FEI</td>
			<td></td>
			<td>For imaging samples</td>
		</tr>
		<tr>
			<td>Iron Oxide Nanopowder/Nanoparticles</td>
			<td>US Research Nanomaterials, inc.</td>
			<td>US3320</td>
			<td>Fe3O4, 98%, 20-3- nm, Silicon oil Coated</td>
		</tr>
		<tr>
			<td>KD Scientific Legato 100 Single-Syringe Pump</td>
			<td>Sigma Aldrich</td>
			<td>Z401358-1EA</td>
			<td>Single syringe infusion pump</td>
		</tr>
		<tr>
			<td>Master Airbrush - Model S68</td>
			<td>TCP Global</td>
			<td>MAS S68</td>
			<td>Nozzle/needle diameter: 0.35 mm</td>
		</tr>
		<tr>
			<td>Mettler Toledo AB265-S/FACT Scale</td>
			<td>Cole-Parmer Scientific</td>
			<td>EW-11333-14</td>
			<td>For weighing polymer and&#160; Nanoparticles</td>
		</tr>
		<tr>
			<td>N2 Gas Regulator</td>
			<td>Any company</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nanoenclosure</td>
			<td>Any company</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Optical Microscopy Glass Slides</td>
			<td>Fisher Scientific</td>
			<td>12-550-A3</td>
			<td>Used as a substrate for fiber mat deposition</td>
		</tr>
		<tr>
			<td>OSP Slotted Bob, 33 mm</td>
			<td>TA Instruments</td>
			<td>402796.902</td>
			<td>Bob, upper geometry</td>
		</tr>
		<tr>
			<td>OSP Slotted Double Gap Cup, 34 mm</td>
			<td>TA Instruments</td>
			<td>402782.901</td>
			<td>Double wall cup, lower geometry</td>
		</tr>
		<tr>
			<td>Oxford BenchMate Digital Vortex Mixer</td>
			<td>Pipette</td>
			<td>VM-D</td>
			<td>Rated up to 4,200 rpm, for mixing solutions</td>
		</tr>
		<tr>
			<td>Oxford Benchmate Tube Roller</td>
			<td>Pipette</td>
			<td>OTR-24DR</td>
			<td>Sample mixer/rotator</td>
		</tr>
		<tr>
			<td>Polystyrene-block-polybutadiene-block-polystyrene</td>
			<td>Sigma Aldrich</td>
			<td>432490-1KG</td>
			<td>styrene 30 wt. %, Mw ~ 185,000 g/mol</td>
		</tr>
		<tr>
			<td>SEM Pin Stub Specimen Mount</td>
			<td>Ted Pella Inc.</td>
			<td>16119</td>
			<td>18 mm diameter x 8 mm height</td>
		</tr>
		<tr>
			<td>Spatula</td>
			<td>VWR</td>
			<td>82027-532</td>
			<td>To load test materials</td>
		</tr>
		<tr>
			<td>Tetrahydrofuran (THF)</td>
			<td>Fisher Scientific</td>
			<td>T425-1</td>
			<td>solvent, HPLC grade</td>
		</tr>
		<tr>
			<td>TRIOS</td>
			<td>TA Instruments</td>
			<td>v4.3.1.39215</td>
			<td>Rheometer software</td>
		</tr>
	</tbody>
</table>

solution blow spinning of polymeric nano-composite fibers for personal protective equipment

Light-weight, protective armor systems typically consist of high modulus (&#62;109 MPa) and high-strength polymeric fibers held in place with an elastic resin material (binder) to form a non-woven, unidirectional laminate. While significant efforts have focused on improving the mechanical properties of the high-strength fibers, little work has been undertaken to improve the properties of the binder materials. To improve the performance of these elastomeric polymer binders, a relatively new and simple fabrication process, known as solution blow spinning, was used. This technique is capable of producing sheets or webs of fibers with average diameters ranging from the nanoscale to the microscale. To achieve this, a solution blow spinning (SBS) apparatus has been designed and built in the laboratory to fabricate non-woven fiber mats from polymer elastomer solutions.
In this study, a commonly used binder material, a styrene-butadiene-styrene block-co-polymer dissolved in tetrahydrofuran, was used to produce nanocomposite fiber mats by adding metallic nanoparticles (NPs), such as iron oxide NPs, that were encapsulated with silicon oil and thus incorporated in the fibers formed via the SBS process. The protocol described in this work will discuss the effects of the various critical parameters involved in the SBS process, including the polymer molar mass, the selection of the thermodynamically appropriate solvent, the polymer concentration in solution, and the carrier gas pressure to assist others in performing similar experiments, as well as provide guidance to optimize the configuration of the experimental setup. The structural integrity and morphology of the resultant non-woven fiber mats were examined using scanning electron microscopy (SEM) and elemental X-ray analysis via energy-dispersive X-ray spectroscopy (EDS). The goal of this study is to evaluate the effects of the various experimental parameters and material selections to optimize the structure and morphology of the SBS fiber mats.

In this study, non-woven fiber mats consisting of poly(styrene-butadiene-styrene) fibers in the nano- and micro-scale, were synthesized with and without the presence of iron oxide NPs. To form fibers, the SBS parameters must be carefully selected for the polymer/solvent system used. The molar mass of the dissolved polymer and the solution concentration are critical in controlling the morphology of the structures produced by the SBS process. In this study, a poly(styrene-butadiene-styrene) block-co-polymer (styrene 30 wt....

Watch this Scientific Journal Video about Solution Blow Spinning of Polymeric Nano-Composite Fibers for Personal Protective Equipment at JoVE.com

Solution Blow Spinning of Polymeric Nano-Composite Fibers for Personal Protective Equipment

The primary goal of this study is to describe a protocol to prepare polymeric fiber mats with consistent morphology via solution blow spinning (SBS). We aim to use SBS to develop novel, tunable, flexible polymeric fiber nanocomposites for various applications, including protective materials, by incorporating nanoparticles in a polymer-elastomer matrix.

Light-weight, protective armor systems typically consist of high modulus (&#62;109 MPa) and high-strength polymeric fibers held in place with an elastic ...

This self protocol covers some of the most important parameters and steps involved in solution blow spinning of polymeric nano composite fibers including polymer molar mass selection of thermodynamically appropriate solvents, polymeric concentration in solution, incorporation of nano materials, carrier gas pressure, and working distance. SPS is a relatively new technique that offers great versatility with respect to the polymer solvent system and the end product. Furthermore, it can be used to rapidly deposit formal fibers onto both planar and non-planar substrates and create sits or webs of fibers of both the nano and microscale diameters.The goal of this work is to provide guidance to develop tunable and flexible polymeric fiber nano composites that can be used as alternatives for typical binder materials found in body armor applications by incorporating nano particles in the fiber's polymer elastomer matrix. Currently, there are no commercially available systems or standard operating procedures to perform a solution blow spinning on tuneable polymeric nano composite fibers. The demonstration of our particle and apparatus could help others to effectively develop their own process for their application.To begin, transfer the desired amount of the dry polymer into a clean 20 milliliter borosilicate glass vial using a small spatula. Place the vial into the chemical fume hood and add approximately 10 milliliters of tetrahydrofuran to achieve a 200 milligrams per milliliter concentration. Then close the vial and place it on the mixer or rotator.Add dry iron oxide nanoparticle powder into a clean 20 milliliter glass vial. Then add 10 milliliters of tetrahydrofuran into the vial and close it. Thoroughly agitate the sample on the vortex mixer until the nanoparticles become invisible at the bottom of the vial and then sonicate the sample for approximately 30 minutes with a two to five minute interval between each sonication, to ensure the complete dispersion of the nanoparticles, and to avoid the sample heating.Add the polymer into the nanoparticle dispersion inside the chemical hood and seal the vial. Then mix it on the rotator at 70 RPM for 60 minutes at room temperature until the polymer completely dissolves. Adjust the height and angle of the airbrush to align with the center of the glass microscope slide attached to the collector and secured in place.Ensure the gas cylinder is properly secured to its wall mount, and connect the gas inlet of the airbrush to the nitrogen pressurized gas cylinder. Turn on the main valve of the gas cylinder and slowly adjust the pressure to achieve the desired flow. Then close the main valve.Secure the substrate on the collector using the equipped vice and adjust the height of the collector to align perpendicular to the spray direction and pattern of the airbrush to deposit the material on the substrate. Identify the optimal working distance by sliding the collector to its furthest position away from the airbrush nozzle. Transfer the polymer nanoparticle solvent mixture into a dissolved gas analysis borosilicate glass syringe equipped with a stainless steel needle.Remove any air bubbles from the sample by holding the syringe with the needle pointing up and tapping the syringe gently then slowly depress the plunger to displace any excess air. Detach the needle, attach the syringe to the syringe pump unit and secure the syringe. Connect the PTFE tubing coming from the outlet of the syringe to the appropriate inlet on the airbrush and select the desired injection rate from the syringe pump unit menu.Open the main valve on the nitrogen gas cylinder for the nitrogen gas to flow through the airbrush and initiate the spraying process by starting the syringe pump unit to dispense the polymer nanoparticle solvent mixture. Observe the spraying pattern and ensure that there are no clogs. Incrementally increase or decrease the injection rate until the solution is spraying freely.Adjust the position of the collector for solvent evaporation by sliding it towards the airbrush until the desired amount of the material is deposited on the substrate. Then stop the syringe pump unit and close the main valve of the nitrogen gas cylinder. At the critical concentration the dissolved polymer coils start to overlap each other and cause entanglement.The calculated and experimentally predicted values of the critical concentration were similar. Therefore, a polymer concentration above the critical concentration was used for the solution blow spinning process. The effect of different polymer concentrations on the fiber mat morphology was studied, and it was observed that undesired polymer beads were present at lower and near the critical overlap polymer concentrations.Pristine and morphologically smooth fibers were obtained at polymer concentrations above the critical concentration. At low magnification the fiber mat generated from a high polymer concentration showed the presence of individual and cylindrically shaped fibers with minimal beads or fiber welding. Higher magnification confirms the absence of polymer beads.The effect of gas pressure on fiber morphology was also studied. As pressure increases the fiber diameter decreases while very high pressure results in large polymer beads and welded fibers. The presence of iron oxide nanoparticles within the polymer fibers was determined using back scattered electron analysis.The elemental analysis further indicated the presence of iron oxide nanoparticles Selection of an appropriate solvent, as well as the molar mass of the polymer in its concentration and solution are some of the most critical parameters that can dictate success or failure of this protocol. The methods described in this protocol can be applied to develop polymeric fiber nano composites for various other fields and applications including biomaterials, polymer based conductive materials, filtration devices, and others.

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Research

JoVE Journal

Engineering

2.5K 조회수.  Material Measurement Laboratory, National Institute of Standards and Technology. 이 자체 프로토콜은 열역학적으로 적절한 용매의 고분자 몰 질량 선택, 용액의 고분자 농도, 나노 물질의 통합, 캐리어 가스 압력 및 작동 거리를 포함하여 고분자 나노 복합 섬유의 용액 블로우 방사와 관련된 가장 중요한 매개 변수 및 단계를 다룹니다. SPS는 폴리머 용매 시스템 및 최종 제품과 관련하여 뛰어난 다양성을 제공하는 비교적 새로운 기술입니다. 또한 평면 및 ?...