Tech review: Electrospinning – Weaving tiny fibres

Electrospinning: An ancient nanotechnology rediscovered for modern demands

Electrosinning, the closely related cousin of electrospraying, is a method of using high voltage electric charge to draw a polymer into a fine fibre [1]. Depending on the strictness of your definition it can be considered a nanofabrication process. Electrospun fibre is commonly between 150 nm to 600 nm with extreme cases being an order of magnitude in either direction [2-3]. This places it neatly between formal nanotechnology (a single dimension less than 100 nm) and traditional microfibers (1-5 µm). The process has been known since the turn of the 20th century, not long after mass production of synthetic polymers began [4]. During the Second World War Soviet researchers developed the technology to produce high performance gas mask filters [5]. The subsequent iron curtain resulted in the technology remaining a forgotten scientific curiosity until it was rediscovered by accident in the early 90’s [6].

Figure 8 - Colour Online Only.jpg "Photo Credit: Robert Lamberts, Plant & Food Research, New Zealand"

Figure 8 – Colour Online Only.jpg
“Photo Credit: Robert Lamberts, Plant & Food Research, New Zealand”

There are three main benefits that electrospun fibre offers [7]. From geometry, the narrow diameter of the manufactured fibre results in a very high surface area to volume ratio ideal for catalytic reactions [8] and similar processes. Due to the high degree of stretching the fibre experiences it is likely that the fibre produced will have a tensile strength that begins to approach the theoretical limit making it of great interest for nanocomposites [9]. Finally, at the nanoscale, mater sometimes obtains new properties intrinsic to its scale leading to applications in filtration and tissue engineering [10]. With emerging consumer concern over nanotoxicology, electrospun fibre has the additional benefit of being relatively unlikely to contaminate biological systems. Electrospinning usually produces one long continuous fibre. Unlike asbestos, the fibre aspect ratio is very high allowing the immune systems defences to cope efficiently with exposure without requiring safety equipment.

"Electrospun poly(vinyl alcohol) fibres embedded with dispersed magnetic nano iron oxide particles"

“Electrospun poly(vinyl alcohol) fibres embedded with dispersed magnetic nano iron oxide particles”

Electrospun fibre does carry some downsides. During manufacture, the fibre is ejected from a highly charged polymer droplet and pushed towards a collector by forces due to carried electric charge and high voltage static fields [11]. Part way through the process, the ejected jet becomes unstable resulting in traditional electrospinning producing random fibre coils spread over the entire deposition area. There are techniques on the market that can produce aligned fibre to varying degrees [1,5,11] however, they are almost all limited to batch processing making scale up challenging. A similar problem extends to precision placement of individual fibres which requires post-handling of the manufactured material. This limits applications in microscale electronics despite the ability to directly create insulated conductive fibres [12]. The final challenge faced by the technology since its discovery is a detailed theoretical understanding of the process itself. The current level of public knowledge often slows down commercial development due to trial and error still being required.

"Lycopodium fungal spore trapped on an electrospun poly(vinyl alcohol) membrane"

“Lycopodium fungal spore trapped on an electrospun poly(vinyl alcohol) membrane”

Electrospinning has the potential to impact many industries. With mater manipulating nanomachines still a long way from practical realization, manufacturing methods that can produce nano structured materials are the logical intermediate step. Using a two-step process it is possible to manufacture most ceramics in the form of nanofibers [13]. These fibres find their use in catalytic chemical reactions, dye sensitized solar cells and piezoelectric energy harvesting. Using conductive polymers it is possible to create conductive meshes or using co-axial technology create insulated fibres. These fibres can find use in sensors by grafting chemical sensor groups to the fibre surface. The same fibres also find use in lithium polymer batteries and high capacity capacitors [14]. The use of co-axial fibre production has also allowed the nascent development of optical waveguide fibres [15]. Rather than use co-axial fibres it is possible to directly mix mutli-component polymer fibres or electrospin multiple fibre types into a single membrane. This technology can be used to produce various energy storage devices or organic solar cells [16].

Vac-High PC-Std. 10kV x1000 (46mm)

Vac-High PC-Std. 10kV x1000 (46mm)

The industrial market for electrospun fibre has experienced variable growth over its history. Early years saw growth driven by entrepreneurs such as Cooly and Morton [4] primarily aimed at the textile industry. Ultimately the technology lost against cheaper manufacturing methods. After the Soviets recognized the value of electrospun fibre for air filtration they started producing “Petryanov filters” and scaled up to 20 million m2 of filter per annum [4-5]. The infrastructure resulting from this industry lives on in one of the largest electrospinning companies Elmarco Ltd., one of the few produces of industrial scale electrospinning equipment. Much like the Soviet utilization of electrospinning, from the 1980’s onward Donaldson Inc. in the USA has been producing high performance filter materials predominantly for military applications [17]. Public information is sparse due to the intellectual property being protected as trade secrets. Other early electrospinning companies include Electrospinz Ltd. and MECC Co. Ltd. producing lab scale equipment. In the modern era there are over 30 companies around the world manufacturing products or machines.

Electrospinning is a fascinating technology with a long rich history. Steeped in potential, the technology has been tackled by a number of great minds but has yet to attract the right scientist or engineer to realize that potential. While electrospinning has seen commercial products developed in the filtration and medical markets, electrospinning has yet to see a company corner the market either in product or technology. These untapped solutions may just be the next solution key to solving a major commercial problem.

Article contributed by Dr. Jonathan Stanger

jonathanstanger

 

References:

[1] S. Ramakrishna, An introduction to electrospinning and nanofibers. Singapore: World Scientific, 2005.

[2] M. Costolo, J. Lennhoff, R. Pawle, E. Rietman and A. Stevens, ‘A nonlinear system model for electrospinning sub-100 nm polyacrylonitrile fibres’, Nanotechnology, vol. 19, no. 3, p. 035707, 2007.

[3] Q. Pham, U. Sharma and A. Mikos, ‘Electrospun Poly(ε-caprolactone) Microfiber and Multilayer Nanofiber/Microfiber Scaffolds:  Characterization of Scaffolds and Measurement of Cellular Infiltration’, Biomacromolecules, vol. 7, no. 10, pp. 2796-2805, 2006.

[4] N. Tucker, J. Stanger, M. Staiger, H. Razzaq and K. Hofman, ‘The History of the Science and Technology of Electrospinning from 1600 to 1995’, Journal of Engineered Fibers and Fabrics, vol. 7, no. 2, pp. 63-73, 2012.

[5] Y. Filatov, A. Budyka and V. Kirichenko, Electrospinning of micro-and nanofibers. New York: Begell House, 2007.

[6] J. Doshi and D. Reneker, ‘Electrospinning process and applications of electrospun fibers’, Journal of Electrostatics, vol. 35, no. 2-3, pp. 151-160, 1995.

[7] J. Stanger, ‘Experimental Assessment of Charge Flow in Electrospinning’, Ph.D., University of Canterbury, New Zealand, 2013.

[8] S. Chuangchote, J. Jitputti, T. Sagawa and S. Yoshikawa, ‘Photocatalytic Activity for Hydrogen Evolution of Electrospun TiO 2 Nanofibers’, ACS Appl. Mater. Interfaces, vol. 1, no. 5, pp. 1140-1143, 2009.

[9] J. Kim and D. Reneker, ‘Mechanical properties of composites using ultrafine electrospun fibers’, Polymer Composites, vol. 20, no. 1, pp. 124-131, 1999.

[10] K. Hofman, N. Tucker, J. Stanger, M. Staiger, S. Marshall and B. Hall, ‘Effects of the molecular format of collagen on characteristics of electrospun fibres’, J Mater Sci, vol. 47, no. 3, pp. 1148-1155, 2011.

[11] A. Andrady, Science and technology of polymer nanofibers. Hoboken, N.J.: Wiley, 2008.

[12]A. Luzio, E. Canesi, C. Bertarelli and M. Caironi, ‘Electrospun Polymer Fibers for Electronic Applications’, Materials, vol. 7, no. 2, pp. 906-947, 2014.

[13] V. Tomer, R. Teye-Mensah, J. Tokash, N. Stojilovic, W. Kataphinan, E. Evans, G. Chase, R. Ramsier, D. Smith and D. Reneker, ‘Selective emitters for thermophotovoltaics: erbia-modified electrospun titania nanofibers’, Solar Energy Materials and Solar Cells, vol. 85, no. 4, pp. 477-488, 2005.

[14] L. Wang, Q. Xiao, Z. Li, G. Lei, L. Wu, P. Zhang and J. Mao, ‘Synthesis of Li2CoTi3O8 fibers and their application to lithium-ion batteries’, Electrochimica Acta, vol. 77, pp. 77-82, 2012.

[15] G. Kwak, G. Lee, S. Shim and K. Yoon, ‘Fabrication of Light-Guiding Core/Sheath Fibers by Coaxial Electrospinning’, Macromol. Rapid Commun., vol. 29, no. 10, pp. 815-820, 2008.

[16] S. Chuangchote and T. Sagawa, ‘Application of Electrospun Nanofibers in Organic Photovoltaics’, Nanostructure Science and Technology, pp. 141-162, 2014.

[17] S. Cavaliere, Electrospinning for advanced energy and environmental applications. CRC Press, 2015.

Industry ready in Bangalore

The ties between IEEE Young Professionals and Industry is crucial. In today’s article we highlight the work of IEEE Young Professionals in Bangalore and how they are ensuring that ensuring industry readiness through a series of events run earlier this year.

The A and A of IoT: A Tutorial on Arduino and Android  Organised at the Robert Bosch Centre for Cyber Physical Systems. The event was organised by IEEE Computer Society (IEEE Bangalore Section), IEEE Young Professionals Bangalore Section and IEEE IoT SIG (IEEE Bangalore Section).

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Every day we see various sensors integrated into product such as a Smartphones, tablets etc. It is only a matter of time before every mechanical machine is coupled with our Smartphone. The A and A of IoT: A Tutorial on Arduino and Android gave an insight wherein people and ʺThingsʺ are connected in an immersively networked computing environment. The past couple of years have seen a heightened interest in the IoT space transcending industry, academia and government.

The day started off by the speaker Gurinder Singh Gill who gave an overview about PCB design aspects, Hardware Design process, Design Considerations, Parts and Tools selection, CAD Design and Layouting, Testing and verifying PCB and Finalizing the Prototype. This was followed up by the speaker Ashish Joglekar who discussed about Mixed Signal Board Design and problems and solutions to EMI considerations. The next session by Mr Gurinder Singh Gill was related to the middleware suite offered by Arduino and Android for building IoT applications. The session deeply stressed on use of arduino boards which links the real world to IoT. An Introduction to Arduino Yun (hardware and software) was provided and then configuring and programming the Yun was taught to us. In the later session by Mr. Vasanth Rajaraman, a working knowledge of these systems and an Introduction to Android, a Open Platform for Mobile Development was provided. We also learnt about the  Development Framework and the Android Architecture. Finally the day was ended by Dr. Prasant Misra, who spoke about the Android for IoT and different Sensors, a mechanism for self-describing devices which forms part of a plug‐n‐play IoT infrastructure that is necessary for interoperability (across platforms from multiple vendors) and successful deployment of large‐scale systems.

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C-DAC Knowledge Park Industry Visit

C-DAC at Bangalore is engaged in carrying out research and delivering solutions and product in area of System Software for PARAM series of super computer. The centre is highly acclaimed as a centre for excellence in the thermatic areas of High Performance and Grid Computing, Cyber security and Cyber Forensic etc. The student members and young professionals had Demo sessions on IoT and Augmented Reality from MARS Lab, along with presentation and visit to Super computer facility conducted by CTSF lab. The student members were explained the necessary and importance of IoT and given a brief introduction about it. They also got an opportunity to visit PARAM PADMA super computer and know its application and its performance in India’s development.  The most interesting bit was session on Augmented Reality with real-time application. The tour was extremely informative and greatly benefitted its attendees and enhanced their knowledge about Super Computer and Recent Technologies.

Industry readiness program 

This 2 day program mainly focused on Aptitude Training and Interview Handling Skills. Students from various parts of North Karnataka, from around 5 different colleges attended this event. aaaa

The first session conducted by Ms. Neena Nair dealt with communication skills, resume building and interview handling. Her session kick started with an ice breaking session which created a gregarious and warm environment. Tricks and knacks on how to crack an interview were taught. Next the students were trained on resume building which gave various ideas on how to polish and refine ones resume. The session seemed to be quite peculiar and interesting for the students as they were able to grasp various things taught by the speaker. At the end of the day, it showed that the students didn’t had any barrier as such with their communication skills.

The second session conducted by Mr. Abhilash Varma dealt with Aptitude training. Topics covered included mathematical thinking and analytical thinking. Various problems on numbers systems, profit and loss, percentages and as well in analytical, verbal and non verbal reasoning were solved. The various shortcuts taught by him to arrive at an answer in less than 10sec were really beneficial. Showing the problems in a pragmatic way made the students to understand them easily. The course material covering most of the topics was distributed. Therefore the students seemed much active during his session and also gave them a solid grip on aptitude.

The speakers were excellent and brilliant in their respective fortes and an overwhelming response from the students was received. The speakers were delighted about the response and cooperation from the crowd. Indeed it was a great platform provided by IEEE to the students, to become well versed with their aptitude and interview handling skills, in order to get placed. And of course, the Non -IEEE members who attended this event are now willing to become an IEEE member. This event was a good example of how Young Professionals can enhance the learning outcomes of students.

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Articles contributed by Nipun Manral

 

Young Professional Update from Iraq

It was not long ago that we reported on IEEE Young Professionals in Iraq and their struggles. With this article we wanted to update all IEEE members on the situation there and some their activities. Despite the raging war and instability our IEEE members are still making the best of their time.

iraqi

IEEE Iraq section and Young Professionals team in collaboration with American University of Iraq, Sulaimaniya (AUIS) ran a scientific workshop in late October based on the topic of “Robotics Sciences”. The purpose of the workshop was to gather all robotics experts and students to share the latest developments in the field. The workshop was conducted in coordination with IEEE Iraq Section represented by Dr. Eng. Sattar B. Sadkhan, Vice chairman of IEEE in Iraq who emphasised the importance of IEEE Robotics society, benefits of being IEEE member to motivate new students of AUIS to join IEEE family. The importance of robotics in disaster recovery was also discussed. Mr. Suhail Al-Awis, IEEE Young Professional and doctoral Candidate from University of Technology, presented the on the use of neural networks in robotics and explained the concept around the investment into neural networks in the implementation of autonomous vehicles.

The topics covered advanced concepts and applications of robotics in general and the role of IEEE in supporting local activities in this field. The interaction created stimulating discussions as well as brainstorming for possible future collaborations and activities in the field of robotics.

The event was concluded with celebrations of IEEE Day 2015. All attendees shared the special IEEE cake in spirit to encourage new volunteers in serving the society by scientific or humanitarian activities which reflect. So dear friends of IEEE, we are well and we are continuing to operate with smiles on our faces. We will continue to contribute in developing technology for the advancement of humanity.

IEEE Iraq Section and Young Professionals

IEEE Iraq Section and Young Professionals