Interview with Margareta Zetterblom

Imagine a classroom with wavy lengths of wool on the walls. A class of shouting school children enters the room. And all of a sudden the wool contracts - to absorb the sound. It is not science fiction, the technology is already here. Someone who knows this to be true is Margareta Zetterblom, corporate postgraduate student and scientist with a focus on smart textiles.

Entering the show room at the small corporation Acqwool outside Gällstad is to be surrounded by softness. Everywhere there is felted wool. In the ceiling a fluffy length of ivory-colored wool, smooth on one side and ribbed on the other, hangs in curves. Spotlights embedded in grey wool direct their light down onto the black, dressed table surface with a bright red runner in the same material. There are bright curtains, multicolored carpets, and wall-high lengths in black, grey, beige, and red wash board structure with front and back sides in different colors - so called Qwaiet Double.

One both feels and hears that everything is made of wool. 
- It is nice and quiet here. There is no echo and no reverberation time, in Margareta Zetterblom's words. Since she began her Master's studies at the Swedish School of Textiles she has specialized in sound insulation with textiles. Today she is a so called minor corporation postgraduate student - with a grant from the Knowledge Foundation. She spends one day a week at Acqwool. The remaining time she works at the Swedish School of Textiles - she is one of the scientists in the Smart Textiles project.

- This room is super insulated, almost too much so. But this kind of room gives a very homely and soft sound environment, Margareta thinks when she describes the effect of the felted wool in the room made for convincing presumptive customers. As visitors we concur. Moreover, it is impossible to refrain from touching everything, from the soft table surface to the broad-gauge sheets of pure natural materials that hangs from rails in the middle of the ceiling.

- Sound and light environment, that it was ecological, sustainable development - all of this had to check out, she says. She made some sketches and weaving samples at the Swedish School of Textiles, tried at Sweden's Technical Research Center, but was met with little interest for producing the specially gauged lengths at the weaving corporations. It would take too long and would be very expensive, they communicated. Instead she sewed the prototypes - with folds of felt she had bought - on her own, by hand.

- Sure, it took time, but I am as pigheaded as anyone! she laughs and contently remarks that the trouble she went through paid off. At the opening ceremony of the day care center was the then executive at Acqwool Pär Jarnebrink - who solemnly assured Margareta Zetterblom that "we can knit that!". - Well, we will see about that! I thought, she admits who were in doubt. But the Gällstad corporation held what they had promised.

- Up until that point we were mostly into products that could preserve heat. Among other things we had made the interiors for the concept cars of a major make. But we knew the wool possessed sound insulating characteristics too, Lars Karlsson, Development Manager at Acqwool, and Per Karlsson, Technical Design at the corporation, says.

- Everything we do still builds on wool, but today we are focussed on sound insulators. It is interesting and we think there is a huge market here, Lars Karlsson explains. For Margareta Zetterblom the igniting spark to go on to specialize in textiles and sound insulation came during her internship at AB Ludvig Svensson in Kinna.

- I was told there was a great demand for new sound insulating products.

- In many public environments noise is a huge problem since the textiles were removed - it should be clean, no fancy work. If textiles are used at all today they are mostly rather thin straight wall lengths that do no good - when it comes to sound. There are no doubts about the functional value of the massive pieces of wool Aqcwool produces at present. That has been established with exact measures by the SP Technical Research Institute of Sweden.

- The trick is to get the density exactly right. If one felts the wool too much it will be too compact and then it will absorb no sound at all. The sound waves must be able to penetrate into the material, as explained by Margareta. Instead of fixed screens covering the entire ceiling - which is the most common sound insulation in public environments today - schools and offices will be able to choose more flexible solutions made of wool, along a wall or to screen parts of the room off when needed, that is the idea. But that is not all. The wool is also to be smarter - it is the intension of Margareta Zetterblom, who is part of a group of scientists in Smart Textiles at the Swedish School of Textiles together with Lena Berglin, Linda Worbin, and Anna Persson. They aim to integrate electronics into textiles - to make it show and feel as little as possible.

- The way these sound insulators work today one may designate them passively smart. But they may become actively smart as well, as described by Margareta Zetterblom. In a corner at the other side of the woollen pieces she crumples a small black cloth with a memory metal knitted into it. When she flips the power switch and the cloth moves and becomes flat.

- There is a reaction when the memory metal heats up. It remembers its original state and strives to return to it. With two different memory metals and a microprocessor that turn the power on and off depending on the change in sound level, the wool that rises up when there is noise - and thus absorbs sound even better - becomes reality, Margareta Zetterblom reasons. It and the speaking collar - instead of headset for the mobile phone or Mp3. An attempt to develop a textile microphone is the aim of a project Margareta Zetterblom is part of together with Lena Berglin, within the frame work of Vinnväxt. In front of us lies a glaring yellow piece of cloth, their first test as to what will happen with the sound when the cable is exchanged for an interwoven conductive metal yarn. The next step is to make so called piezoelectrical elements - which many microphones have - in textile material.

- We have that part moving. If we can integrate the microphone in a knitted structure you may talk into the collar of your jacket instead of using a headset, Margareta Zetterblom says enthusiastically. She sees no end to the possibilities in modern day textiles - with both function and aesthetical appeal.

- What we do in the Smart Textiles project in Borås is to connect competences that previously have not found any common ground to work on. Now we work towards the same goal when we make for example prototypes and that inspires entirely new ideas.

- Also, it is a clear advantage that in this town there are always doors open towards the textile industry - most of which resides in these parts, anyway.

- Right now my feeling is that smart textiles is one of the fields where Sweden and Borås may be at the very front line of research! Margareta Zetterblom concludes.

Text: Karin Tufvesson 
Photo: Lena Bryngelsson