FAQ

General Nanofibers

What are nanofibers?

Nanofibers, also often referred to as polymeric nanofibers, lack a widely accepted formal definition. Informal nonwovens, textile and other engineered fiber industry jargon will often accept the term nanofibers for fibers with any diameter size smaller than 1,000 nanometers, or 1 micron. Elmarco’s equipment makes the finest, most uniform nanofibers that are commercially available and produced on industrial scale equipment. We define nanofibers as fibers with a diameter of less than 500 nm capable of being produced in a continuous mat with fiber size uniformity that has a standard deviation of 30% or less.

Are nanofibers the same as carbon nanotubes? Are they used in fiber optic communications?

No, nanofibers are not the same as carbon nanotubes, nor are they used in fiber optic communications. There are a number of applications, many of which are pursued by our customers, where carbon nanotubes are implanted in the nanofiber web. Nanofibers are seldom, if ever, used as a stand-alone fiber. They are most often found as continuous sheets, or mats, and are similar to materials produced in the nonwovens industry.

What are nanomaterials?

ISO Technical Committee 229, which is charged with defining standards in the field of nanotechnology, considers nanomaterials as those materials that are typically but not exclusively below 100 nm in at least one dimension.

What is nanotechnology?

Nanotechnology is a broad term that defines technology that exists in the nano-scale, most often sub-100 nm. For reference, if we took a one meter wide object and grew it to the size of the Earth, 1 nanometer would be only a marble, and a nanofiber would be a basketball or beach ball. Nanotechnology often defines the precision construction and control of materials – often times they take the perspective of building up, using some kind of molecular self-assembly, or by taking a top down approach. Polymeric nanofibers are almost always constructed using a top down approach.

Nanotechnology allows materials to have well controlled surface area to volume ratios. All nanomaterials have settings in which their performance is incremental to current benefits, and areas where their benefits are revolutionary. This question of incremental vs. revolutionary can only be determined by measuring performance in the end product. Similar to our inability to predict the intricacy of flocking behavior from observing a single bird, the behavior of a large quantity of nanoparticles is difficult to predict until they are assembled and measured – the interactions defy conventional software modeling.

What are nanofibers used for?

Nanofibers have a very broad range of applications. First patented in the US in 1902 (#692,631), nanofibers have long been used in air filtration and many other areas. Liquid filtration applications followed shortly thereafter and thick webs of nanofibers can function like membranes. Nanofibers have increasingly found their way into all areas of nonwovens as production prices have fallen and manufacturing robustness has increased, including: medical barriers, protective garments, face masks, cosmetics, hygiene, acoustic and thermal insulation, battery separators, tissue scaffolds and even fashion. Adoption of nanofiber technology is driven by the surface area, pore size and other materials properties of the nanofiber web. Cutting edge research continues in many areas, but particularly in medicine and energy. Just as falling prices and scale allowed microfibers to enable new products and industries, the same is expected for nanofibers.

Nanospider(TM) Technology

How are nanofibers made?

There are two main methods for producing nanofibers: Nozzle and Nanospider(TM).

Nozzle. From a research perspective, the most common introduction to nanofibers comes from a needle, nozzle or spinneret apparatus configured at a lab bench. A polymer is placed into solution and through hydrostatic pressure it is extruded from the tip while a voltage gradient is applied between the tip to a collector plate. A glass slide, nonwoven, textile or paper can be used as a substrate to collect the nanofiber sheet as it is formed. The major variables in producing nanofibers on such an apparatus are: the viscosity of the polymer, the conductivity of the polymer, the amount of pressure applied through the needle, the amount of voltage passed between the needle and the collector, the gap between the needle and the collector and finally the conductivity of the substrate. Nozzles are well-suited for initial work in the lab environment; however, they show difficulties in scaling to production capacity because the mechanical complexity of such equipment leads to lower quality, greater downtime and higher production costs.

Free surface. Free surface electrospinning methods do not use nozzles, needles or spinnerets. Nanospider™, a free surface electrospinning process that is available commercially in equipment made by Elmarco, controls the following variables: the viscosity of the polymer, the conductivity of the polymer, speed of the rotation of the electrode or “roller” in the polymer bath, the amount of voltage passed between the electrode and the collector, the gap between the electrode and the collector and finally the conductivity of the substrate. Similar to how nozzle work can be done in a sealed container with a controlled atmosphere, many free surface methodologies allow for this as well. Free surface electrospinning has been shown to be straightforward in converting from lab to production scales without the pricing and production issues seen in many nozzle-based processes.

What is the difference between nozzle and Nanospider(TM) production methods?

The main difference in production variables is the use of hydrostatic pressure in the nozzle process. This causes fouling, irregular nanofiber mats, reduced nanofiber diameter conformity and higher production costs. The Nanospider(TM) process has been repeatedly demonstrated at production scale with a diverse range of customers.

I work with a nozzle process now, will it scale to Nanospider(TM)?

Yes. We have helped a number of customers transition their process from a nozzle to our Nanospider(TM) lab equipment. Our lab equipment has special small volume attachments for those who are just scaling from small volumes.

What polymers are you most familliar with?

Our customers that have purchased industrial scale equipment have focused their efforts on Nylon 6 (PA6) and polyvinyl alcohol (PVA).

Our lab equipment customers have demonstrated many kinds of polymer and solvent combinations, many of which we have transitioned to our production scale equipment. A sample of those polymers is listed below:

Other manufacturers have listed concerns with getting nanofibers integrated into a manufacturing environment – what is your view?

Our goal at Elmarco is to allow you the capability of making the highest quality nanofibers in your facility. Our team of engineers has helped our customers work with countless substrate, nanofiber and production process combinations. As you look to bring nanofibers in house, our equipment is only one part of your engagement with Elmarco. We go the extra step to make sure the equipment works with your entire production facility and supply chain.

What are the most important measures in understanding nanofibers?

There are many important measurements to consider when evaluating a nanofiber solution, be it as part of a standard rolled good, as a surface coating or as a free standing nanofiber mat (or nanofiber membrane).

Both the individual nanofibers and the webs formed from the nanofibers require accurate measurement and description in terms of their diameter, uniformity, length, web thickness, web structure, web size, fiber packing density, and production speed.

Nanofiber diameter: Electrospinning routinely results in fibers with diameters ranging from 500 nm to 50 nm, though there is some difficulty in obtaining smaller sizes for some polymer systems. Larger diameter beads and other structures can be created as needed to add tertiary morphology to the nanofiber web.

Nanofiber uniformity: Uniformity is usually defined in terms of standard deviation of the fiber diameter across the nanofiber web. This can vary broadly by production methodology, but a fiber diameter standard deviation of less than 20% is achievable with many methods. (Note that some applications use nanofibers with larger fibers to intentionally create a broad dispersion of fiber size and therefore a heterogeneous web.) Uniformity of nanofiber coverage across the web can be important in some applications.

Nanofiber length: Often expressed in the textile measure of deniers, which is the weight in grams of a fiber 9,000 meters in length. Denier measurements are often below 0.01 for nanofibers, but are obviously dependent on the specific gravity of the polymer.

Nanofiber web thickness: This is expressed as grams per square meter, often denoted as gsm. This measure is often referred to as the ‘basis weight’ and indicates the thickness of the nanofiber web. Typical measures for nanofiber coatings are from 0.03 gsm to 1.0 gsm. Free standing nanofiber webs (which have membrane-like potential and are often used in liquid filtration) can have basis weights from 1 – 60 gsm. Thicker webs are possible. Thickness can also be referred to as ‘layers’ however this term varies greatly by process. Measurement based on actual thickness is possible as well.

Nanofiber web structures / Tertiary web morphology: As mentioned above, nanofiber webs can include additional structures and characteristics to improve the performance of the end applications. This can include beads, hollow nanofibers, fracture nanofibers and controlling the surface of the nanofibers. These beads can be referred to as caps or shot. Often times, other nanoparticles such as carbon nanotubes, are added somewhere in the manufacturing process to imbue desired properties for the nanofiber web’s end application.

Nanofiber web width and length: How wide and long is the nanofiber web or sheet? These characteristics of the web are defined more by the production process and become a significant concern as a nanofiber process is transitioned from a research to a production environment. Production equipment of 1.6 meters wide is available commercially and is capable of handling traditional rolled good as a substrate to produce long, uniform nanofiber layers.

Fiber packing density (fibers per given area / weight): For certain applications, the number of fibers in a given area, measured by meters of fiber per square cm can be a more important measure than gsm. Further, in certain areas, such as membranes, measures like BET surface area, which show the square meters of surface area for a given weight, can be very important as well.

Production speed: When incorporating nanofibers into a production environment out of the lab, there are many ways to measure the production speed. Keeping other critical measures like gsm, fiber diameter and fiber uniformity constant, nanofiber production capabilities often default to standard textile definitions and focus on square meters of material produced per annum. Properly configured equipment can produce upwards of 40 million square meters per annum, with PA6 as the polymer, 0.03 gsm basis weight, fiber diameter of 200 nm with a standard deviation of fiber size of 20%.

Nanospider(TM) Equipment

What product lines do you have?

We have two core product lines: Nanospider(TM) lab equipment and Nanospider(TM) production lines.

What size nanofibers can your Nanospider(TM) equipment produce?

Our equipment is capable of making Nanofiber equipment at 80, 100, 150, 200, 250 nm or higher.

What widths can you manufacture nanofiber webs?

Nanospider(TM) production equipment is capable of running at 1.6 meters wide. We sell Nanospider(TM) lab equipment that is capable of making nanofiber webs either 20 cm or 50 cm wide.

How uniform are the nanofibers in the Nanospider(TM) web?

All our processes target a standard deviation of mean fiber size of less than 30%.

You mentioned nanofiber coating as opposed to a nanofiber mat, what is the difference?

Nanofiber coatings are applied to a substrate in basis weights of 0.10 gsm or less. Free standing nanofiber webs, or mats, are typically 10 gsm or heavier.

Can Nanospider(TM) equipment be installed in line with other manufacturing processes?

Yes, it can. Our equipment comes with standard shop floor control systems that allow them to be easily integrated.

What are the common variables controlled on Nanospider(TM) equipment?

Nanospider™ equipment uses the same controls allowing you to define the essential process variables for your application. The following five variables are controlled in the same manner on all Elmarco equipment.

• Voltage
• Collector height
• Substrate speed
• Electrode rotation speed
• Chamber atmosphere

Nanofibers in Application

How will nanofibers impact my product?

It is very difficult to tell prior to final testing. If smaller fiber diameters have traditionally improved performanc, it can be assumed that performance will continue to improve. We have, however, seen a number of products where there is a truly revolutionary improvement in performance in the end product.

What kind of certified test results have you produced?

We have independently verified test results for air filtration, anti-microbial and flame retardant properties of materials produced off of our equipment. We have a number of other test results we have secured on other products from Universities and development partners.

Are processes transferable from your lab equipment to production lines?

Yes. We have helped a number of customers transition projects from the Nanospider(TM) lab equipment to full production lines. The unique, nozzle-free aspects of the Nanospider(TM) make this transition easier.

Working with Elmarco

Can we get samples of your material?

Yes. Please email or call us to get our standard set of sample materials. Samples are available for free.

Where can I see your equipment and work with you on prototypes?

We maintain a state of the art technical facility at our headquarters in Liberec, Czech Republic. In addition to our partnership with the Technical University of Liberec, we host an annual Nanofiber symposium and are always pursuing new and novel ways to help our customers make their products better with nanofibers. Our facility has three pilot lines of our industrial scale equipment and over a dozen pieces of lab equipment.

Is it possible to visit your facility?

Yes. Liberec is about one hour North of Prague and we are always happy to host groups as long as their trips are arranged in advance.

How do you charge for prototype work?

We charge for prototype work on a per diem rate depending on the complexity and duration of your needs. Our goal is to document everything you need to make a smooth transition to production and we will work with you to make it easy for your customers to see the benefits nanofibers have to their end products.

How long does it usually take to produce prototypes?

Prototype work depends on many variables, including your own product design. Once a final product design is determined and all of the materials and parameters confirmed, it usually takes 3 – 4 weeks to complete production at our technical facility.

How long does it take to get equipment?

A Nanospider(TM) lab unit takes 8 weeks to get to deliver. An Nanospider(TM) production line takes 18 weeks

Do you offer spare parts and customer service?

Yes. Industry standard contracts are available.

Will you only produce and sell machines, or will you also produce nanofibers as well?

At Elmarco, we make the equipment that makes nanofibers. We do use our technical center in Liberec to support customers as they transition to production.

Who should I contact in case of interest in cooperation in the development of nanofiber materials?

Elmarco equipment and expertise is in the middle of the most interesting nanofiber development projects. Contact us to learn how you can participate at sales@elmarco.com.

Who shall I contact, should I have further question concerning the technology?

Just send an email to the sales department sales@elmarco.com.

About Elmarco

Where is Elmarco located?

Elmarco is headquartered in Liberec, Czech Republic, one hour North of Prague. We also have offices in Raleigh, NC, USA and outside of Tokyo, Japan.

Which office should I contact?

Any office can handle your inquiry and put you in touch with the right people.

What common tenants guide your product development?

As a supplier to the semiconductor sector since 2000, Elmarco’s Nanospider™ equipment builds on our long-standing tradition of customer-focused engineering. We have five design principles;

• High quality nanofibers. Everything we design into our Nanospider™ equipment is focused on allowing our customers to incorporate the highest quality nanofibers into their products.
• Ease of use. Just because you are new to nanofibers doesn’t mean your equipment should be elaborate. Nanospider™ equipment uses industry standard control modules, terminology and measures in order to ensure that it is easily incorporated into your production environment, supply chain and products.
• Scalable. Start with our research equipment and then grow to a production line. The work done on Elmarco’s Nanospider™ lab equipment transitions to Nanospider™ production lines.
• Modular. Elmarco’s equipment is designed to be modular. Start with a single Nanospider™ NS 1600 production line to pilot your initial production and plant integration. Scale up by adding additional NS 1600 lines in serial to your existing configuration or bringing in other NS 1600 lines to your other facilities.
• Flexible. Elmarco will work with you to help configure your production equipment, help you optimize your polymer selection and pair that with the appropriate substrates (nonwoven, cellulose or otherwise). Nanospider™ equipment is easily configured for your application and end products.

Where does the name Elmarco come from?

Elmarco was founded by Ladislav Mares to pioneer new technologies and bring them to the marketplace. He used the Czech pronunctiation of his intiials to name the firm: L = El, and M = Mar.