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August 2019 http://www.technical-textiles.net ISSN 1752-2668 ©2019 International Newsletters Ltd

the news service for textile futures

Special Feature: Electrospinningnanofibrous composite yarn page 5

Patch can measure electro- andseismocardiography page 8

Printed medical devices withtextile-like properties page 10

In this issue full contents on page 2…

The thickness and elasticity of the fabricwound dressing can be customized tothe needs of specific areas of the body,and the nanofibres can be absorbed bythe skin’s own tissue as it heals.

Two synthetic materials – polyviny l -pyrrolidone and polyglycerol sebacate(PGS) – were blended to producenanofibres using a nozzle-free electro -spinning device, which comprises arotating cylinder above a pool ofsolution containing the two

components. As the cylinder spinsunder high voltage and temperature,tiny fibres are quickly produced fromthe liquid and spun onto an adjacenthot surface. The fabric is formed asthe fibres cool.

According to the researchers, PGS isstretchable and compatible with humantissue. Tests on skin cells showed thatthe nanofibres provide a scaffold onwhich newly formed skin can grow.

Dr Norbert Radacsi of the University’sSchool of Engineering said the techniquerepresents a cost-effective way of makingartificial skin that can be adapted for allareas of the body, to accelerate thewound healing process. The fact thatthe fabric can be absorbed by the bodywould negate the need for frequentdressing changes.

The researchers will now focus onfurther developing and testing thematerial for medical use, which theyexpect will take about four years.

See also: Medical Engineering & Physics,In press, Nozzle-free electrospinning of

polyvinylpyrrolidone/poly(glycerol sebacate)fibrous scaffolds for skin tissue engineeringapplications; http://dx.doi.org/10.1016/j.medengphy.2019.06.009

Contact: Antonios Keirouz, Schoolof Engineering, Institute forMaterials and Processes,University of Edinburgh.Tel: +44 (131) 650-1000. Fax: +44 (131) 650-6554.Email: [email protected];https://www.eng.ed.ac.uk

Nanofibres

Portable systemfor electrospinningwound dressings Nanomedic of Lod, Israel, islaunching what it describes asthe first portable system for theelectrospinning of nanofibrouswound dressings.

Nanofibres

Synthetic skin could aid wound healingEngineers from the UK’s University of Edinburgh and Empa, Swiss Federal Laboratories for MaterialsScience and Technology, in St Gallen have manufactured a thin artificial skin from nanofibres.

Artificial skin produced fromnanofibres at the University of

Edinburgh. Photo: Antonios Keirouz.

The device (SpinCare) can be used to create dressings,the surface texture, size and shape of which canbe customized to the needs of a given wound. SpinCareapplies the dressing from a short distance from thepatient, eliminating contact between the caregiver andthe wound, reducing the risk of infection. Further,combinations of additives, such as antibacterials,antibiotics, collagen, cannabinoids and hydrogels, canbe integrated into the electrospun nanofibres.

The SpinCare system comprises a hand-held device anda sterile, pre-filled syringe of solution. According toNanomedic, it:

• creates a dressing that can accommodate any wound sizeand body contour, eliminating the need to keep a largeinventory of conventional bandages;

• is transparent, facilitating the inspection of the wound;• eliminates the need for dressing changes; • automatically peels away from the wound as

epithelialization (a function of wound healing) occurs.

The Director of Plastic and Reconstruction Surgery atTheNational Care Burn Centre in Shelpa, Israel, ProfessorJosef Halik , says that electrospun nanofibres are similarto the structure of body tissue and, as a result, provide anexcellent medium for tissue integration and regeneration.

Contact: Chen Barak, Chief ExecutiveOfficer, Nanomedic.Tel: +972 (0)8-915-3001.Email: [email protected];http://www.nanomedic.com

Smart textiles

Metal-coated nonwovenfor protecting electronic-information carriersA nonwoven has been developed for theprotection of electronic-information carriers bythe Technical University of Liberec andVecerník of Pencín, both in the Czech Republic.

The nonwoven is designed to prevent the unauthorizedaccess of information stored on vulnerable contactlesscarriers such as credit cards, passports and identity cards, aswell as smartphones, tablets and laptops. Many of thesedevices contain radio-frequency identification (RFID), near-field communication (NFC) or similar integrated circuits orchips that allow the reading of stored informationremotely—possibly without the owner’s knowledge.

The nonwoven disclosed in International Patent PublicationWO2019/072322 is designed to protect against suchmisuse, while demonstrating resistance to repeated

ContentsSPECIAL FEATURENovel electrospinning process for industrial-scale compositenanofibrous yarn production 5

NANOFIBRESSynthetic skin could aid wound healing 1Portable system for electrospinning wound dressings 1

SMART TEXTILESMetal-coated nonwoven for protecting electronic-information carriers 2

NANOMATERIALSFlame-retardant nanoclay-modified fabrics 3Nanotube producer makes billion-dollar company list 4

WEARABLE TECHNOLOGYPrintable, stretchable, washable electronics for wearable technologies 4

Sepsis can be easily detected by wearable monitoring system, says Isansys 7Next-generation patches from Covestro 8Ultrathin and stretchable patch can measure electro-and seismocardiography 8

AUTOMOTIVEAutomotive seat covers made from trilaminate foams 9

FIBRESElastic fibres made from carbon dioxide being readied for mass-production 9

EVENTSSustainability and digitization to be key themes at Dornbirn 10Diary of Events 11

ADDITIVE MANUFACTURINGPrinted medical devices with textile-like properties 10

2 Smart Textiles and Nanotechnology—August 2019

Nanomedic says that SpinCare creates ananofibrous dressing, the properties of which can be

fine-tuned to the condition of a patient’s wound.

deformations, low stiffness and high elasticity. The nonwovencan be further processed by conventional manufacturingmethods such as gluing, lamination, layering and sewing.

The nonwoven is made of synthetic fibres, preferablpolyethylene terephthalate (PET), with a metal surfacecoating and exhibits high air permeability (breathability) anda low bending stiffness, which allow it to be used in acomposite with layers of other textiles. It has an arealdensity of 5–60 g.m–2 and a thickness of 50–200 µm.

The nonwoven first undergoes a process such as calenderingor pressing to make the surface flat and smooth, reducingthe likelihood of it interfering with electromagnetic waves,before it is coated with a metal layer. The preferred metal forthe coating is copper, which is said to have an excellentshielding capability and high mechanical bending strength, andis relatively cheap. Other metals, such as silver or tin, can beadded to impart corrosion resistance to the copper. Thecoating can be applied using autocatalytic methods as a sub-micron layer that envelops only the fibres—it does not formmetal surfaces between the fibres.

The inventors say the coating imparts a significant increasein electrical conductivity, as well as a considerable increasein the ability of the material to shield an electromagneticfield, without affecting its air and water vapour permeabilityor bending stiffness (flexibility).

The nonwoven can be protected on both sides by othertextile or non-textile layers, such as woven, knitted or othernonwoven textiles, leather, artificial leather or foil, which canbe bonded by, for instance, gluing or sewing.

The resulting composite textile can be used to produceprotective cases for credit cards and other contactlessinformation carriers such as travel documents, as well ascases for portable electronic devices.

See also: International Patent Publication WO2019/072322,Textile for the protection of electronic information carriers;Applicants: Technická univerzita v Liberci and Vecerník s.r.o.;Inventors: Jirí Militký, Veronika Tunáková, Zuzana Hrubošováand Josef Vecerník.

Contact: Technická univerzita v Liberci.Tel: +420 (485) 353612.https://www.tul.cz; or:

Večerník s.r.o.Alšovice 54, CZ-46821 Pěnčín, Czech Republic.

Nanomaterials

Flame-retardant nanoclay-modified fabricsFlame-retardant nanoclay-modified fabrics thatcan be used as flame barriers in mattresses and

bedding have been developed by PrecisionCustom Coatings and Precision Textiles, bothof Totowa, New Jersey, USA.

The fabrics outlined in US Patent 10 260 195 cancomprise viscose fibres (10) modified with nanoclays (claynanoparticles) (12), which are distributed throughout thefibre matrix (14). The fibres can also incorporateinherently flame-resistant polymers and/or cellulosicmaterials. The use of the nanoclays eliminates the need toapply flame-retardant coatings to the fabrics.

Nanoclays are primarily formed from phyllosilicates (layeredaluminosilicate minerals), which delaminate in aqueousmedia to form platelets with thicknesses of as small as 1 nm,and lengths and widths in ranges from tens to hundreds ofnanometres, or in the micron range.

Suitable nanoclays include bentonites, montmorillonites,hectorites, illites and kaolinites; organically modifiednanoclays can also be used.

The nanoclay can be mixed or dispersed into a flowablepolymer or solution of polymeric precursors, which is thenextruded using conventional methods to form the clay-modified fibres. The nanoclay content of the fibre is typically60–70% by weight.

The inventors explain that when the modified fibreis ignited, the nanoclay particles migrate from the matrixto its surface, forming a barrier to mass and heattransport. Further, the nanoclay-filled barrier is non-combustible and provides structural reinforcement tothe charred fibre.

The fabrics disclosed in the Patent are said to offer enhancedflame-retardant characteristics when used as high-loft fireblockers with nonwovens made from inherently flame-

Smart Textiles and Nanotechnology—August 2019 3

Scanning electron micrograph showing cross-sections of nanoclay-modified fibres developed byPrecision Custom Coatings and Precision Textiles.


retardant fibres, especially in the construction of mattresses,as well as in domestic bedding and upholstered items.

See also: US Patent 10 260 195, Nanoclay-modified fabricsfor flame retardation; Applicants: Precision Custom CoatingsLLC and Precision Textiles LLC; Inventors: ChristopherKeith Martin and Aneta Konior.

Contact: Precision Custom Coatings LLC.Tel: +1 (973) 890-3873. Fax: +1 (973) 890-9248.https://pcc-usa.com; or:

Precision Textiles LLC.Tel: +1 (973) 890-3873. Fax: +1 (973) 785-8180.Email: [email protected];https://precisiontextiles-usa.com

Wearable technology

Printable, stretchable,washable electronics forwearable technologiesA process to screen-print circuits that arestretchable and washable onto flexible substratesfor use in wearable technologies, includingmedical applications, has been developed byConductive Transfers of Barnsley, UK.

The company says that the process eliminates the wires andplastic substrates found in existing wearables. Screenprinting is used to build-up layers of ink, including one ormore electrically conductive layers, onto a coated plasticsheet (transfer film). The conductive layers are encapsulatedbetween two electrically insulating ink layers and can alsobe stretchable. An adhesive layer is added to forma conductive transfer, which can then be heat-pressed ontoany surface, including textiles. The transfer film is finallypeeled off, leaving the ink-stack bonded to the substrate.

Speaking at the Techtextil trade fair in Frankfurt am Main,Germany, held on 14–17 May 2019, Director of ConductiveTransfers Paul Brook said the process can be used to addtechnology, including sensors, heaters and surface-mountcomponents, to existing garment designs, while retaininghigh levels of comfort. He added that the health sector isone of the company’s largest customers, with its technologybeing used in electrocardiography, pressure mats andmuscle stimulation.

In November 2018, the signed an agreement with AtlanticTherapeutics of Galway, Ireland, to manufacture and supplystretchable, washable circuits for its new Innovo product forthe treatment of urinary incontinence(1).

See also: (1)Smart Textiles and Nanotechnology, July 2019, Non-invasive pelvic floor exercise powered by stretchable electronics,page 4; https://www.technical-textiles.net/node/74910

Contact: Paul Brook, Director, ConductiveTransfers Ltd.Tel: +44 (114) 321-6596.Email: [email protected];https://www.conductivetransfers.com; or:

Steve Atkinson, Chief Executive Officer,Atlantic Therapeutics.Tel: +353 (91) 475470.Email: [email protected];http://www.atlantictherapeutics.com

Nanomaterials

Nanotube producermakes billion-dollarcompany listOCSiAl, which claims to be the world’s largestmanufacturer of carbon nanotubes (CNTs),was recently added to the CB Insights GlobalUnicorn Club, a list of start-up companiesvalued at US$1 billion or more.

The company made the list after Russian investor A&NNInvestments of Moscow acquired a 0.5% stake in thecompany for US$5 million, suggesting that the company as awhole is worth US$1 billion. The valuation has caused somecontroversy in Russia, where it has been disputed by at leastone economist(1).

OCSiAl says that it was the first company to produce high-quality CNTs, which can be used to increase the strength andelectricaland thermal conductivities of a variety of materials,on an industrial scale. The company says that, when it enteredthe market in 2014, it sold CNTs at a price that was 75 timeslower than those already on the market and that its revenueshave been doubling annually ever since.

The President of OCSiAl, Yuriy Koropachinskiy, says: “Todaywe are observing the emergence of markets for its [CNT]application and what is important is that these include notonly the high-tech sector, but also mass-produced goods. ”

The company is rapidly increasing its output and in 2022plans to put the first stage of the world’s largest CNTsynthesis plant into operation in Luxembourg, itsinternational headquarters. OCSiAl’s customers includecarmakers, electronics companies and chemical producers.

Koropachinskiy says: “We believe the company will beworth at least US$100 billion in ten years’ time.”

See also: (1)https://www.intellinews.com/russia-s-state-owned-tech-agency-claims-its-first-unicorn-161677

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Developed at the Technical University of Liberec inCzechia, alternating current (AC) electrospinning reallyneeds to be seen to be fully appreciated(1), and enablesthe mass-production of nanofibrous composite yarnsthat can be further processed using standard textiletechnologies. As such, the process could enable the high-volume production of new types of textiles with a varietyof unique functionalities.

“We believe this approach may well lead to the widespreadproduction and use of composite nanofibrous yarns on anindustrial scale,” says Petr Žabka of the Liberec Departmentof Textile Machine Design research and development (R&D)team behind the development.

Current limitationsNanofibre webs and coatings are already essential materialsfor a range of applications, including protective materials,sensors, cosmetics, filtration and energy-storage products.

The most widely researched and used technology for theproduction of nanofibres so far is electrospinning, which in aresearch environment or in limited production runs, yieldshighly promising results thanks to its versatility andsimplicity. There are two widely used variants of the process;that using nozzles; nozzle-less electrospinning. Both employdirect current (DC) electric fields.

The first involves the formation of nanofibres from a jet ofliquid polymer that is ejected from a nozzle. The nozzle acts asone electrode and a collecting plate forms another, such thatthe jet emerges into a high-voltage, longitudinal electric field.The dominant fibre-forming mechanism is the whippingelongation that occurs as a result of bending instability, althoughsecondary splitting of the liquid polymer streams can also occur.

Unfortunately, the number of jets needed to reach aneconomically acceptable rate of productivity is high, typicallyin the thousands. This results in challenges in respect of thereliability of the process, the consistency of quality and themaintenance of the machinery, not least keeping it clean.

In its simplest form, a nozzle-less electrospinning headconsists of a rotating drum that is dipped into a liquid bath(a polymer solution or a polymer melt). The drum emergesfrom the bath carrying on its surface a thin layer of liquidthat becomes exposed to an electric field generatedbetween the drum and the collector. If the voltage exceedsa critical value, the field generates a number ofelectrospinning jets.

In such a system, the jets self-organize, forming theoptimum number and spacing according to the settings of

the process variables (such as the field’s voltage, and theviscosity and surface tension of the liquid). In turn, this leadsto significant improvements in the process stability and theconsistency of the quality of the nanofibre layers produced,compared with conventional electrospinning frommultiple nozzles.

Nozzle-less electrospinning has been commercialized byElmarco, itself a spin-off from the Technical University ofLiberec, and although it increases throughput in comparisonwith electrospinning using nozzles, the general efficiency ofthis method still remains relatively low(2).

A further drawback of DC electrospinning is that bothvariants require a collector, which makes it difficult tocombine it easily with other technologies, owing to thepresence of the high electric field strength within thespinning zone.

Key inventionsAC electrospinning is said to overcome many of theseproblems. It is based on two key inventions in which a

SPECIAL FEATURE

Novel electrospinning process for industrial-scalecomposite nanofibrous yarn productionThe extraordinary process of alternating current (AC) electrospinning, which works without eithernozzles or a collector, was demonstrated at ITMA 2019 (in Barcelona, Spain, on 20–26 June) tocrowds of curious onlookers. Editor Adrian Wilson was among them, and reports on the process.

The plume of nanofibres resembles fine smokeemerging from the alternating currentelectrospinning electrode.

SPECIAL FEATURE

smoke or aerogel-like plume of interconnected nanofibres isejected from a spinning electrode and transported by anelectric wind – gas flows that are driven by ions generatedby corona discharges and accelerated in an applied electricfield – in the direction of an axially rotating and ballooningcore yarn.

Crucially, there is no collector. Instead, a self-organizedcounter-electrode is formed repeatedly in the immediatevicinity of the spinning electrode. This counter-electrodeconsists of electrically charged nanofibre segments. Thegroups of nanofibres created by the spinning electroderapidly alternate (every 10 ms) between being eitherpositively or negatively charged, corresponding to therespective positive or negative charge generated by theAC power supply. Alternately charged nanofibrous groupsfrom successive emissions attract eachother to form whatis described as a nanofibrous plume, which is then moved at0.25–0.6 m.s–1 by an electric wind created by thespinning electrode.

Since there is no collector to form an obstacle along the ACspinning line, significantly higher throughputs can beachieved and the line could be linked easily to furtherdownstream production equipment, such as knitting orweaving machines.

Further, the compact nature of the nanofibrous plumeenables almost 100% of its mass to be trapped by thespinning and ballooning yarn core. The core yarn, thelinear density of which can range from tens to thousands ofdtex, is unwound from a master bobbin and fed horizontallyinto the spinning space 150 mm above the spinningelectrode, where it is twisted and looped into the shapeof a balloon using two rotating devices. Thanks to thismotion, the core yarn is tightly enveloped by nanofibreswhere they contact it.

The process by which the nanofibrous envelope is formed iscomplex. High-speed camera recordings show that theplume of nanofibres is not entirely plastic and exhibits a

partially elastic behaviour that helps tighten the nanofibrousenvelope around the core. This elasticity is a result of thestructure of the plume. Both in its elasticity and in structure,the plume resembles a fibrous web created by drumcarders from staple fibres.

Even when several plumes of nanofibres are wound-up froma set of AC spinning units, the two co-rotating devices ensurethe almost uninhibited rotation and ballooning of the yarn.

The composite yarn resulting from the process is thenwound onto an output bobbin. It is worth noting that inthe operation of the line, there is no risk of injury to theoperator by residual voltage after it is switched off, as is thecase with DC electrospinning technology.

Industrial scaleOne application for these materials, Žabka suggests, is theproduction of a porous artificial proboscis, which could beused to collect tiny liquid samples. Nanofibrous yarnscould also be used to produce woven and knitted fabrics,macramé and laces with mechanical, sorption and filtrationproperties that significantly differ from those ofconventional textiles. Nanofibrous textiles also have greatpotential for use in medicine.

“Composite yarns produced by our technology obviouslyhave better sorption and filtration properties than classicyarns for capturing harmful substances in filters,” Žabka said.“They can be applied for instance, as industrial, agriculturaland domestic water-purification devices. Thanks to the highproduction rate of our method, these linear flexible materialswill potentially be quite cheap and therefore well accessibleto wide social groups for use as filters, sorption membranesand sutures.”


Cross-section of a composite yarn with a polyester multifilament core, with a nanofibrous envelopemade from polyamide 6.

The axis of the yarn core and the axis of thenanofibrous plume emitted from the spinning

electrode are almost perpendicular to one another.


SPECIAL FEATURE

PatentsThe technology for AC electrospinning and the productionof nanofibrous composite yarns is protected by four Czechpatents (CZ304137, CZ306428, CZ306772 and CZ07745).

All four national patents have been assigned withInternational Applications:

• WO2014/094694 A1, Method for the production ofpolymeric nanofibres by spinning of a solution or polymer meltin a field, and a linear formation from polymeric nanofibresprepared by this method;

• WO2017/108012 A1, A method for producing polymericnanofibres by electrospinning and a polymer solution or amelt, and spinning electrodes for the production ofpolymeric nanofibres equipped with at least one suchspinning electrode;

• WO2016/192697 A3, Linear fibrous formation with acoating of polymeric nanofibres enveloping and supportinglinear formation constituting a core, a method and a devicefor producing it;

• WO2019/047990 A1, Method for producing polymericnanofibres by electric or electrostatic spinning of a polymersolution or melt, a spinning electrode for the method, and adevice for production of polymeric nanofibers equippedwith at least one such spinning electrode.

International Application WO2014/094694 A1 hasalready been granted in the USA as US10041189 B2, inChina as CN105008600B, in Japan as JP6360492 B2 andin Russia as RU2672630 C2. International ApplicationWO2017/108012 A1 has already been granted in theUSA as US505245015.

References(1)A short film of the process can be viewed here:https://bit.ly/2JyAChx

(2)Technical Textiles International, September 2014,Production technologies create opportunities for nanofibres,page 13; https://www.technical-textiles.net/node/296

Further InformationDavid Lukáš, Professor, Department ofNonwovens and Nanofibrous Materials, TechnicalUniversity of Liberec.Tel: +420 (495) 353-158.Email: [email protected]; or:

Jaroslav Beran, Department of Textile MachineDesign, Technical University of Liberec.Email: [email protected]; or:

Petr Žabka, Department of Textile MachineDesign, Technical University of Liberec.Email: [email protected]; http://www.fs.tul.cz

Contact: Alexander Bezrodny, Vice President,Research and Development, OCSiAl.Tel: +352 2799-0373.Email: [email protected];https://ocsial.com

Wearable technology

Sepsis can be easily detectedby wearable monitoringsystem, says IsansysHospitals are supposed to put a patient on anantibiotic drip within an hour if sepsis issuspected, but research by BBC News(1)

suggests a quarter of patients in England waitlonger. Delays increase the chance ofpotentially fatal complications such as organfailure and even death.

This problem could be solved easily, says Isansys Lifecareof Oxford, UK, because the company’s Patient StatusEngine (PSE) wireless monitoring system, which canrapidly detect the onset of sepsis, is alreadycommercially available.

The system employs body-worn smartpatch sensors tocollect vital signs automatically and continuously. Associatedsoftware then uses this data to identify any changes in apatient’s condition and alerts clinicians to what could be theearly onset of sepsis more quickly than would otherwise bethe case.

The Chief Executive Officer (CEO) of Isansys, Keith Errey,says: “Being able to identify patients at the highest risk ofdeterioration is key for clinicians and nurses. Too often theirworkloads are overwhelming and they do not have time toobserve their patients closely at all times. Our technologydoes this for them.”

Although the PSE has been trialled in UK National HealthService (NHS) hospitals, it is not yet available for standardcare in the UK. Hospitals throughout Europe, the US, Indiaand Australia, meanwhile, currently are working onprogrammes to adopt PSE for the monitoring of patients.

Isansys is also working with the Northwell Health Group inNew York City, USA, on a major study that shows that thecontinuous wireless monitoring of mothers in labourusing PSE promises new insights into neonatal care, withmaternal fever being a significant predictor of early onsetneonatal sepsis.

The Sepsis Trust of Birmingham, UK, believes there areabout 250 000 cases of sepsis, and more than 50 000deaths from it, every year in the UK.

...Continued from page 4

See also: (1)https://www.bbc.co.uk/news/health-48749985

Contact: Keith Errey, Chief Executive Officer, IsansysLifecare Ltd.Tel: +44 (1235) 436225.Email: [email protected];http://www.isansys.com

Wearable technology

Next-generation patchesfrom CovestroA prototype electronic patch has beenproduced using breathable thermoplasticpolyurethane (TPU) films by researchers atthe Holst Centre and Covestro.

Wearable electronic patches are already being used in manyareas of medicine, including patient monitoring anddiagnosis, and market demand is rising rapidly, in line withthe growing digitization of the healthcare sector. Thesepatches must be worn for extended periods of time andtherefore must be comfortable, while also adhering skin.

In response, Covestro of Leverkusen, Germany, hasdeveloped its Platilon breathable TPU materials, which aresuitable for the production of patches using roll-to-rollmanufacturing processes. Using a process developed by theHolst Centre of Eindhoven, The Netherlands, the electronicscan be printed on the film and embedded in a thermo -formable polyurethane (PU) foam, which is then coveredwith a second film layer. The patch is then treated with aspecial skin-compatible adhesive, which bonds firmly to theskin, but allows the patch to be removed painlessly. Theadhesive system and the thermoformable foam are based onCovestro’s Baymedix PU raw materials.

With 2018 sales of €14.6 billion, Covestro is one of theworld’s largest polymer suppliers.

Contact: Frank Rothbarth, Media Relations, Covestro. Tel: +49 (214) 6009-2536.

Email: [email protected];http://www.covestro.com

Wearable technology

Ultrathin and stretchable patchcan measure electro- andseismocardiographyA wearable patch based on a soft and stretchablepiezoelectric polymer could make heart-healthmonitoring easier and more accurate than ispossible using existing electrocardiograph (ECG)machines—a technology that has changed littlein almost a century.

Developed at The University of Texas at Austin in theUSA, the patch is the latest version of Associate ProfessorNanshu Lu’s electronic tattoo (e-tattoo), a device thatcan be placed on the skin to measure a variety of bodyresponses, from electrical to biomechanical signals. Lu saysthat the device is so lightweight and stretchable that it canbe placed over the heart for extended periods with little orno discomfort.

Powered remotely by a smartphone, the e-tattoo is the firstsuch device to measure both ECG and seismocardiography(SCG) simultaneously. While ECG records the rates ofelectrical activity produced each time the heart beats,SCG measures chest vibrations associated with heartbeats.

“We can get much greater insight into heart health by thesynchronous collection of data from both sources,” says Lu.ECG readings alone are not accurate enough to determinethe health of a patient’s heart, but they provide additionalinformation when combined with SCG signal recordings.Like a form of quality control, the SCG verifies the accuracyof the ECG readings.

Although soft patches for ECG sensing are not new, manyare still made from non-stretchable materials, making thembulky and uncomfortable to wear. Lu and her team’s


Polyurethane products from Covestro are suitablefor the efficient production of electronic patches

using roll-to-roll processes.

Developed at the University of Texas, the e-tattoo ismade of a piezoelectric polyvinylidene fluoride.

e-tattoo is made of the piezoelectric polymer polyvinylidenefluoride, capable of generating its own electric charge inresponse to mechanical stress. Three-dimensional (3D) digitalimage correlation (DIC) is used to map chest vibrations toidentify the best location to mount the e-tattoo.

Lu and her team are already working on improvements todata collection and storage for the device, as well as waysto power the e-tattoo wirelessly for longer periods. Theyrecently developed a smartphone app that not only storesthe data safely, but can also show a heart beating on thescreen in real time.

See also: Advanced Science, Volume 6, Issue 14,A chest-laminated ultrathin and stretchable e-tattoo for themeasurement of electrocardiogram, seismocardiogram, andcardiac time intervals,http://dx.doi.org/10.1002/advs.201900290

Contact: Nanshu Lu, Associate Professor,Cockrell School of Engineering, The University ofTexas at Austin. Tel: +1 (512) 471-4208. Email: [email protected];https://www.ae.utexas.edu/faculty/faculty-directory/lu

Automotive

Automotive seatcovers made fromtrilaminate foamsA method for producing automotive seatcovers from trilaminate foams has beendeveloped by Magna International of Aurora,Ontario, Canada.

According to the company, seats with concavities of over10 cm in depth can be produced using the technology(FreeForm), which is impossible when using cut-and-sewtechniques for producing seat covers. Further, designfeatures with radii as small as 3–4 mm (rather thanthe conventional limit of 20–25 mm) can be produced onseat covers and the method can be applied to any textile,leather or polymer surface specified by carmakers.

The company says that the highly concave lower back-seatshapes, when coupled with bolsters, offer a high degree ofsupport to their occupants, and that FreeForm seat coversare four-times more breathable than moulded alternatives.Because they employ hidden tie-downs the need for up to80 traditional trim attachment components is eliminated.Soft-touch, concave back panels for front seats can beproduced that provide up to ten centimetres of additionalrear-seat knee clearance.

The Global Vice President of Advanced TechnologyEngineering for Magna Seating, Dino Nardicchio, says: “The

FreeForm process is flexible and can be used in both low-and high-volume vehicle programmes. We have had a greatreaction from [carmakers] and expect to see FreeFormseats start appearing in 2020–2021 vehicles.”

The use of textiles in automotive interiors will be a topic ofdiscussion at the first edition of Textile Opportunities in aChanging Automotive Industry, which will take place inBirmingham, UK, on 5–6 February 2020.

Contact: Tracy Fuerst, Global Director of CorporateCommunications and PR, Magna International.Tel: +1 (248) 631-5396.Email: [email protected];http://www.magna.com; or:

Jill Gwinnutt, Marketing Manager, TextileOpportunities in a Changing Automotive Industry.Tel: +44 (0)870 1657210.Email: [email protected]; https://www.technical-textiles.online/TOAI

Fibres

Elastic fibres made fromcarbon dioxide beingreadied for mass-productionCovestro, together with the Institute of TextileTechnology (ITA) at RWTH Aachen Universityand various textile manufacturers, havesucceeded in making elastic fibres from carbondioxide (CO2) and are now looking toindustrialize the process.

The thermoplastic polyurtethane (TPU) elastic fibres arebased on a partially (up to 20%) CO2-based precursorcalled cardyon, which is already used to producepolyurethane (PU) foams for mattresses and sports


FreeForm trilaminate foam seat-cover technologycan be applied to any textile, leather or plastic.


floorings. The fibres are produced using a melt-spinningtechnique in which the TPU is melted, pressed into very finethreads and finally processed into a yarn of endless fibres.Unlike dry spinning, which is used to produce conventionalelastic synthetic fibres, melt spinning eliminates the need forenvironmentally harmful solvents, according to Covestro ofLeverkusen, Germany.

The resulting fibres are both elastic and resistant to tearing.Several companies from the textile and medical engineeringsectors have already tested the fibres and have converted theminto yarns, socks, compression tubes and tapes.

The development of the fibre production process has beenfunded by the European Institute of Innovation andTechnology (EIT) in Budapest, Hungary, and it will now beoptimized as part of the CO2Tex project, which is to be paidfor by the German Federal Ministry of Education andResearch (BMBF). CO2Tex is part of BioTex Future project,an initiative set-up by RWTH Aachen University in Germanyto develop production and processing technologies for themanufacture of textiles from bio-based polymers.

The Chief Executive Officer (CEO) of Covestro,Markus Steilemann, says: “This is a further, highly promisingapproach to enable ever broader use of CO2 as an alternativeraw material in the chemical industry and expand the rawmaterials base. Our goal is to use CO2 in more and moreapplications in a circular economy process and save crude oil.”

Contact: Petra Schäfer, Communications, CovestroDeutschland AG.Tel: +49 (214) 6009-6332.Email: [email protected]; http://wwwcovestro.com; or:

Viola Siegl, Press Relations and Marketing Manager,Institut für Textiltechnik, RWTH AachenUniversity (ITA).Tel: +49 (241) 80-23421. Fax: +49 (241) 80-22422.Email: [email protected];http://www.ita.rwth-aachen.de

Events

Sustainability and digitizationto be key themes at DornbirnThe digitization of the supply chain for theproduction of textiles and the impact of thetextiles industry on the environment will bekey themes at the Dornbirn Global FiberCongress (Dornbirn-GFC) in Austria on 11–13September 2019.

Among the highlights:

• oceanographer Sarah-Jeanne Royer of the ScrippsInstitution of Oceanography in San Diego, California, USA,

will present her findings on the degradation of plasticsand microfibres in the world’s oceans;

• Commercial Lead at Microsoft of Seattle, Washington,USA, Robert Rosellen, will give a presentation on theways in which software can be used to manage recyclingand sustainability initiatives;

• Security Researcher at Palo Alto Networks in Santa Clara,California, USA, Stefan Achleitner, will discuss the importanceof cyber security for digital manufacturing operations.

For the 58th edition of the annual conference, the organizer,the Austrian Fibers Institute of Vienna, has worked withaccountancy firm PricewaterhouseCoopers (PwC) ofLondon, UK, to put together an event for new companies,50 of which will give presentations.

During the main conference, meanwhile, the latestdevelopments in technology for the fibre and textileindustries will be presented by a line-up of over100 speakers.

The 57th conference, held on 12–14 September 2018,included more than 100 presentations, and attracted over700 participants representing 30 countries.

Dornbirn Global Fiber Congress Office.Tel : +43 (1) 319-2909-41. Fax : +43 (1) 319-2909-31.Email: [email protected];http://www.dornbirn-gfc.com

Additive manufacturing

Printed medicaldevices with textile-like propertiesLooking to emulate and support soft tissuessuch as muscles and tendons, researchers at theMassachusetts Institute of Technology (MIT)have designed pliable, three-dimensionally (3D)printed mesh materials, the flexibility andtoughness of which can be tailored.

3D printing has been used successfully in the manufactureof medical devices such as hearing aids, dental crowns andprosthetic limbs. Such devices, however, are typically printedfrom solid, relatively inflexible materials. By contrast, thestretchable, fabric-like structures developed at MIT could beused in the production of personalized, wearable supportssuch as ankle or knee braces, or even implantable devicessuch as hernia meshes.

As a demonstration, the team has printed a flexible meshfor use in an ankle brace. They have designed the structureso that it prevents its wearer’s ankle from turning inward –a common cause of injury – while allowing the joint tomove freely in other directions. A knee brace that canconform to the knee even as it bends and a glove that

Diary of EventsSEPTEMBER 201910–11 SeptemberE-TextilesPhiladelphia, Pennsylvania, USA.Chris Jorgensen, Director, TechnologyTransfer, IPC - Association ConnectingElectronics Industries.Tel: +1 (847) 597-2826. Fax: +1 (847) [email protected]://www.ipc.org

11–12 SeptemberWearable Technologies AsiaBangkok, Thailand.Marius Janta, Consultant, WearableTechnologies AG.Tel: +49 (8152) 998860. [email protected]://www.wearable-technologies.asia

11–13 SeptemberDornbirn Global Fiber CongressDornbirn, Austria.Dornbirn Global Fiber Congress Office.Tel: +43 (1) 319-2909-41. Fax: +43 (1) [email protected]://www.dornbirn-gfc.com

16–19 SeptemberAvantexParis, France.Barbara Kurdziel, Avantex Paris ShowDirector, Messe Frankfurt France SAS.Tel: +33 (1) 5526-8989. Fax: +33 (1) [email protected]://avantex-paris.fr.messefrankfurt.com/paris/en.html

25–26 SeptemberHealthcare Sensor InnovationsCambridge, UK.Cath Davies, Event Manager, IDTechEx.

Tel: +44 (1223) [email protected]://www.idtechex.com/healthcare-sensor-innovations/show/en

OCTOBER 201922–23 OctoberFunctional Fabric FairPortland, Oregon, USA.Steve McCullough, Reed Exhibitions.Tel: +1 (203) 840-5953. [email protected]://www.functionalfabricfair.com

NOVEMBER 201912 NovemberE-Textiles EuropeMunich, Germany.Chris Jorgensen, Director, TechnologyTransfer, IPC - Association ConnectingElectronics Industries.Tel: +1 (847) 597-2826. Fax: +1 (847) [email protected]://www.ipc.org

Editor: Adrian Wilson

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conforms to a wearer’s knuckles,providing resistance against involuntaryclenching that can occur following astroke, have also been produced.

“This work is new in that it focuseson the mechanical properties andgeometries required to support softtissues,” says Sebastian Pattinson,who took part in the research as apostdoctoral researcher at MIT and isnow at the University of Cambridge inthe UK.

The team’s flexible meshes wereinspired by the pliable, conformablenature of fabrics. “3D-printed clothingand devices tend to be very bulky,”Pattinson says. “We were trying to thinkof how we can make 3D-printedconstructs more flexible andcomfortable, like textiles and fabrics.”

He found further inspiration in collagen,the structural protein that makes-upmuch of the body’s soft tissue. Under amicroscope, collagen can resemblecurvy, intertwined strands, similar toloosely braided elastic ribbons. Whenstretched, this collagen initially doesso easily, as the kinks in its structurestraighten, but once taut, the strands areharder to extend.

Inspired by collagen’s molecularstructure, Pattinson designed wave-likepatterns, which he 3D-printed fromthermoplastic polyurethane (TPU). Hethen fabricated a mesh configurationthat resembles stretchable, yet tough,pliable fabric. The taller the waves, themore the mesh could be stretched atlow strain before stiffening—a designprinciple that can help to tailor a mesh’sdegree of flexibility and helps it tomimic soft tissue.

The researchers printed a long strip ofthe mesh and tested the level ofsupport it provided to the ankles ofseveral healthy volunteers. For eachvolunteer, the team adhered a stripalong the length of the outside of theankle, in an orientation that theypredicted would support the ankle if itturned inward. They then put eachvolunteer’s ankle into an ankle-stiffnessmeasurement robot called the Anklebot.The Anklebot moved each ankle in12 different directions, and thenmeasured the force the ankle exertedwith each movement, both with the

mesh and without it, to understand howthe mesh affected the ankle’s stiffness indifferent directions.

In general, they found the mesh increasedthe ankle’s stiffness during inversion,while leaving it relatively unaffected as itmoved in other directions.

The team’s ankle brace was made usinga relatively stretchable material, but forother applications, such as implantablehernia meshes, it might be useful to usea stiffer material that is at the same timejust as conformable. To this end, theteam developed a way to incorporatestronger, stiffer fibres and threads into apliable mesh, by printing stainless-steelfibres over regions of an elastic meshwhere stiffer properties were needed.They then printed a third elastic layerover the steel to sandwich the stifferthread into the mesh.

The combination of stiff and elasticmaterials can give a mesh the ability tostretch easily up to a point, after whichit starts to stiffen, providing strongersupport to prevent, for instance, amuscle from overstraining.

The team also developed two othertechniques to give the printed mesh analmost fabric-like quality, enabling it toconform easily to the body, even whilein motion.

“One of the reasons textiles are soflexible is that the fibres are able to moverelative to eachother easily,” Pattinsonsays. “We also wanted to mimic thatcapability in the 3D-printed parts.”

In traditional 3D printing, a material isprinted through a heated nozzle, layerby layer. When heated polymer isextruded, it bonds with the layerunderneath it. Pattinson found that, oncehe printed a first layer, if he raised theprint nozzle slightly, the material coming

out of the nozzle would take a littlelonger to land on the layer below, givingthe material time to cool. As a result, itwould be less sticky. By printing a meshpattern in this way, Pattinson was ableto create layers that, rather than beingfully bonded, were free to move relativeto eachother, and he demonstrated thisin a multilayer mesh that draped overand conformed to the shape of agolf ball.

Finally, the team designed meshes thatincorporated auxetic structures—patterns that become wider whenpulled. They were able, for instance, toprint meshes, the middle of whichconsisted of structures that, whenstretched, became wider rather thancontracting as a normal mesh would.This property is useful for supportinghighly curved surfaces of the body. Tothat end, the researchers fashioned anauxetic mesh into a potential knee braceand found that it conformed tothe joint.

“There’s potential to make all sorts ofdevices that interface with the humanbody,” Pattinson says. “Surgical meshes,orthoses, even cardiovascular deviceslike stents—you can imagine allpotentially benefiting from these kindsof structures.”

See also: Advanced Functional Materials,Online version, Additive manufacturing ofbiomechanically tailored meshes forcompliant wearable and implantable devices,https://doi.org/10.1002/adfm.201901815

Contact: Sebastian Pattinson,Assistant Professor, Department ofEngineering, Cambridge University.Tel: +44 (1223) 766141.Email: swpatt@mit-edu; https://www.sebastianpattinson.com;or:

http://www.mit-edu.com


The flexiblemeshes

produced at theMassachusetts

Institute ofTechnology

were inspired bythe pliable,

conformablenature

of fabrics.

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