Advanced manufacturing methods allow industries to push the envelope in cost-effective high-throughput production. Today, roll-to roll processing, or R2R, plays a pivotal role in a wide range of manufacturing fields including flexible solar panels, flexible electronics, thin-film batteries, medical products and membranes. Now, thanks to an innovative new approach by SmartMembranes, R2R manufacturing has taken another leap forward.
A spin-off from the Fraunhofer Institute for Mechanics of Materials, SmartMembranes was founded in 2009 by Dr Petra Goering and Monika Lelonek whose backgrounds are in physical and electrochemistry. “We basically have two product materials,” says Lelonek. These are macroporous silicon wafers and nanoporous alumina, which is a ceramic material. “They are special because they are porous materials with perfectly straight and aligned air channels, meaning they don’t have a sponge-like structure, and the pore size can be adjusted from 25nm up to 10 or 15 microns. So you get these pores all over the complete surface of the membrane which can’t be done with any other process at this moment.” These products can end up anywhere from DNA diagnostic tools to fuel cells, and from fifty different customers there can be fifty different applications.
Having grown to become the leading manufacturer of high-ordered porous silicon and alumina membranes, the company has recently entered the world of R2R through nanoscale developments of the printing process. Their new innovation concerns antireflective (AR) applications, such as flat panel displays for TVs or smartphones. AR surfaces use foils polymers of bioinspired nanostructures that mimic the eye of a moth. These nanostructures resemble lots of tiny bumps on the foil polymer. The production process to obtain these bumps is complicated at the nm scale and because it involves many different types of lithographic steps, it can be very expensive. There are also limitations to the size of the bumps that can be produced and the surface area you want to structure. The maximum right now is 600x600mm. This is then put around a printing cylinder and ‘stitched’ together.
The current limitations and problems with R2R are related to the seam that arises from the stitching. SmartMembranes technique is different. “Instead of creating bumps on a foil polymer surface we do the negative, so we make holes,” explains Lelonek. “By printing the holes inside the foil we create the bumps. It’s basically the vice versa part. What we do is etch an aluminium cylinder completely with our pores all around at once so that there is no stitching anywhere. You can roll all the time and make different sizes, without any size limitations at all. This is seamless R2R with nm structures, so it’s something very new.”
At the cutting-edge is ideally where SMEs should be, developing technologies until they are sufficiently de-risked to attract investors, but it can be a difficult position to maintain when production process are as costly as these. SmartMembranes currently receives R&D federal funding from the German government and is now looking into funding instruments that the EC has set up for SMEs like this. Lelonek explains why they are so attractive: “the different instruments and programmes are very interesting to us. We are not taking part in those right now but we are planning to do so. The SME instrument is really nice because you have to develop a very good product for mass production later on.”
Although it is not yet certain which of their products will be forward for funding, it is clear that there is a very real market interest in the R2R cylinder venture. As a young company with a small team, SmartMembranes have a size disadvantage due to the sheer range of fields their products are employed in, because marketing for so many different applications takes up so much time. But it also means they have the advantage of reaching a wide variety of markets. “We’ve already asked some of our key customers about our new product and the interest is very, very high. More so than other applications even though it’s a completely new area for us. So this is one of the key technologies we will be following for the next years at SmartMembranes,” says Lelonek.
Made in Europe, for Europe. It’s a vision central to the success of the European economy in the years to come but according to Lelonek, the electronics markets is a little different. While most of the electronic components in televisions and other devices using AR flat panel displays come from the US or Asia, the suppliers for Asian companies are often European. Lelonek explains: “they think of German or UK technology, for example, as superior. European technology is seen almost as a brand, something they rely on more than the Asian technology sometimes. For us, there are some competitors for the lithographic part of the process but what we do is so new, for this specific application, that we actually have no competitors we know of right now, possibly worldwide.”
There might be more competition after Lelonek shows off what SmartMembranes has achieved at this year’s ENF2017. Two years ago Lelonek was at the conference in Riga to talk about the company’s membranes and materials, less so about the applications. Having won the award for best exhibitor, ENF2015 was such a success for them that they are back this year and focusing on the applications to attract customers. “It’s not only important to find new customers, though, you also need to find new partners for joint development and projects,” says Lelonek. “Sometimes you need some specific areas or know-how that’s missing from your company. So we’re going show people what’s possible with our membranes and products.”