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Persson, Nils-Krister
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Publications (10 of 72) Show all publications
Euler, L., Guo, L. & Persson, N.-K. (2024). Influence of the electrolyte concentration and amount on the performance of textile electrodes in electrostimulation: A systematic study. Sensors and Actuators A-Physical, 366, Article ID 115010.
Open this publication in new window or tab >>Influence of the electrolyte concentration and amount on the performance of textile electrodes in electrostimulation: A systematic study
2024 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 366, article id 115010Article in journal (Refereed) Published
Abstract [en]

Background

 

Textile-based stimulation electrodes are a fast-growing research area. With their advantages including flexibility, reusability and the possibility for integration into garments, textile electrodes open up new possibilities that are not yet feasible today, e.g. various self-administrated treatments and rehabilitation based on neuromuscular electrical stimulation (NMES) or transcutaneous electrical nerve stimulation (TENS). So far, most research has shown that textile-based stimulation electrodes perform more reliable when wetted with an electrolyte. However, there is no systematic investigation about which type and amount of electrolyte to use.

 

Methods

 

In this study, double-layered textile electrodes have been produced by machine knitting with a size of 3 × 3 cm2. The electrodes were wetted stepwise with a liquid amount from 5 µL up to 320 µL; four levels of sodium chloride (NaCl) concentrations, i.e. 0.9%, 1.5%, 5% and 35%, plus pure deionized water as a reference liquid were chosen. The study analyzed the behavior of the skin-electrode impedance when changing the moisture content and NaCl concentration. In addition, equivalent circuits were modelled for deeper insights into the mechanisms causing an impedance change.

 

Results

 

Results showed that the impedance was greatly influenced by the liquid amount with amounts of 5 µL already significantly reducing the impedance compared to dry electrodes, caused by a substantial reduction in resistance. The reactance, on the other hand, was only partly influenced by the liquid amount showing a reduction upon higher liquid amounts only within a range of 5 – 40 µL. Further, a significant influence on the impedance by the presence of ions was found where the skin-electrode systems wetted with NaCl solution were showing generally lower impedances than systems wetted with deionized water. However, within this, no remarkable influence of the NaCl concentration could be observed. As the impedance was found to be very sensitive to the moisture content in the system, it is recommended to introduce standardizations for impedance testing of wet textile electrodes with precisely controlled electrolyte volumes and liquid migration properties to make independent studies of textile electrodes more comparable.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
smart textiles electrodes physiology
National Category
Textile, Rubber and Polymeric Materials
Research subject
Textiles and Fashion (Design)
Identifiers
urn:nbn:se:hb:diva-31360 (URN)10.1016/j.sna.2024.115010 (DOI)001156311600033 ()2-s2.0-85182396566 (Scopus ID)
Funder
Vinnova
Available from: 2024-01-21 Created: 2024-01-21 Last updated: 2024-02-28
Huniade, C., Bashir, T. & Persson, N.-K. (2023). A pilot line to functionalise textile fibres for textile actuators. In: : . Paper presented at EuroEAP 2023: Eleventh International Conference on Soft Transducers and Electromechanically Active Polymers, Bristol, June 6-8, 2023.
Open this publication in new window or tab >>A pilot line to functionalise textile fibres for textile actuators
2023 (English)Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Textile actuators are at their infancy within the field of electromechanically active polymers. Crude fabric coatings as well as coated pieces of yarns can certainly perform actuation. However, they do not fully consider the capabilities of textile processes and structures. To allow for such possibilities, it is required to have a sufficient supply of processable functional fibres. The presented pilot line is designed to produce said functional fibres from commercial textile yarns. The three continuous processes composing the pilot line are: the layered dip coating using a PEDOT:PSS based solution, the electrodeposition of polypyrrole (PPy) onto the PEDOT coated fibres, and the ultraviolet cured dip coating of ionogels (i.e. dipping followed by UV curing). The continuous aspect of the processes is a key element for fabric manufacturing. Indeed, even the smallest usable fabric requires a substantial length of yarn. This is one of the reasons why the produced fibres were tested on an industrial knitting machine, the other reason being to test their processability. Additionally, a series of tests have been done on the fibres to obtain their conductive, tensile and, if applicable, actuative properties. Therefore, we present a pilot line producing knittable PEDOT coated fibres, textile muscle fibres and ionofibres.

Keywords
textile fibres, continuous production, conducting polymers, ionic liquids, i-textiles
National Category
Textile, Rubber and Polymeric Materials
Research subject
Textiles and Fashion (General)
Identifiers
urn:nbn:se:hb:diva-29916 (URN)
Conference
EuroEAP 2023: Eleventh International Conference on Soft Transducers and Electromechanically Active Polymers, Bristol, June 6-8, 2023
Projects
WEAFING
Funder
EU, Horizon 2020, 825232
Available from: 2023-06-16 Created: 2023-06-16 Last updated: 2023-06-21Bibliographically approved
Juthberg, R., Flodin, J., Guo, L., Rodriguez, S., Persson, N.-K. & Ackermann, P. W. (2023). Correction to: Neuromuscular electrical stimulation in garments optimized for compliance (European Journal of Applied Physiology, (2023), 123, 8, (1739-1748), 10.1007/s00421-023-05181-9). Springer, 123(8)
Open this publication in new window or tab >>Correction to: Neuromuscular electrical stimulation in garments optimized for compliance (European Journal of Applied Physiology, (2023), 123, 8, (1739-1748), 10.1007/s00421-023-05181-9)
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2023 (English)Other (Other academic)
Abstract [en]

The original version of this article unfortunately contained a mistake. A small error in the energy-formula. The original correct formula should be (Formula presented.) 

Place, publisher, year, pages
Springer, 2023
Keywords
erratum
National Category
Physiology
Identifiers
urn:nbn:se:hb:diva-30299 (URN)10.1007/s00421-023-05211-6 (DOI)000984650200001 ()2-s2.0-85158092698 (Scopus ID)
Available from: 2023-08-14 Created: 2023-08-14 Last updated: 2024-02-01Bibliographically approved
Mehraeen, S., Asadi, M., Martinez, J. G. G., Persson, N.-K., Stålhand, J. & Jager, E. W. H. (2023). Effect of Core Yarn on Linear Actuation of Electroactive Polymer Coated Yarn Actuators. Advanced Materials Technologies, Article ID 2300460.
Open this publication in new window or tab >>Effect of Core Yarn on Linear Actuation of Electroactive Polymer Coated Yarn Actuators
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2023 (English)In: Advanced Materials Technologies, E-ISSN 2365-709X, article id 2300460Article in journal (Refereed) Published
Abstract [en]

Smart textiles combine the features of conventional textiles with promising properties of smart materials such as electromechanically active polymers, resulting in textile actuators. Textile actuators comprise of individual yarn actuators, so understanding their electro-chemo-mechanical behavior is of great importance. Herein, this study investigates the effect of inherent structural and mechanical properties of commercial yarns, that form the core of the yarn actuators, on the linear actuation of the conducting-polymer-based yarn actuators. Commercial yarns were coated with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) to make them conductive. Then polypyrrole (PPy) that provides the electromechanical actuation is electropolymerized on the yarn surface under controlled conditions. The linear actuation of the yarn actuators is investigated in aqueous electrolyte under isotonic and isometric conditions. The yarn actuators generated an isotonic strain up to 0.99% and isometric force of 95 mN. The isometric strain achieved in this work is more than tenfold and threefold greater than the previously reported yarn actuators. The isometric actuation force shows an increase of nearly 11-fold over our previous results. Finally, a qualitative mechanical model is introduced to describe the actuation behavior of yarn actuators. The strain and force created by the yarn actuators make them promising candidates for wearable actuator technologies. © 2023 The Authors. Advanced Materials Technologies published by Wiley-VCH GmbH.

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
conducting polymers, electroactive polymers, isotonic and isometric actuation, polypyrrole, textile actuators, Electrolytes, Mechanical actuators, Plastic coatings, Polypyrroles, Smart textiles, Wearable technology, Wool, Yarn, Core yarns, Electromechanically active polymers, Ethylenedioxythiophenes, Mechanical behavior, Polymer based, Property, Structural and mechanical properties, Textile actuator
National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:hb:diva-30277 (URN)10.1002/admt.202300460 (DOI)001022417800001 ()2-s2.0-85163851078 (Scopus ID)
Available from: 2023-08-15 Created: 2023-08-15 Last updated: 2024-02-01Bibliographically approved
Sundström, C., Juthberg, R., Flodin, J., Guo, L., Persson, N.-K. & Ackermann, P. W. (2023). Effects on hemodynamic enhancement and discomfort of a new textile electrode integrated in a sock during calf neuromuscular electrical stimulation. European Journal of Applied Physiology
Open this publication in new window or tab >>Effects on hemodynamic enhancement and discomfort of a new textile electrode integrated in a sock during calf neuromuscular electrical stimulation
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2023 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327Article in journal (Refereed) Published
Abstract [en]

Purpose: To compare fixed transverse textile electrodes (TTE) knitted into a sock versus motor point placed standard gel electrodes (MPE) on peak venous velocity (PVV) and discomfort, during calf neuromuscular electrical stimulation (calf-NMES). Methods: Ten healthy participants received calf-NMES with increasing intensity until plantar flexion (measurement level I = ML I), and an additional mean 4 mA intensity (ML II), utilizing TTE and MPE. PVV was measured with Doppler ultrasound in the popliteal and femoral veins at baseline, ML I and II. Discomfort was assessed with a numerical rating scale (NRS, 0–10). Significance was set to p < 0.05. Results: TTE and MPE both induced significant increases in PVV from baseline to ML I and significantly higher increases to ML II, in both the popliteal and femoral veins (all p < 0.001). The popliteal increases of PVV from baseline to both ML I and II were significantly higher with TTE versus MPE (p < 0.05). The femoral increases of PVV from baseline to both ML I and II were not significantly different between TTE and MPE. TTE versus MPE resulted at ML I in higher mA and NRS (p < 0.001), and at ML II in higher mA (p = 0.005) while NRS was not significantly different. Conclusion: TTE integrated in a sock produces intensity-dependent increases of popliteal and femoral hemodynamics comparable to MPE, but results in more discomfort at plantar flexion due to higher current required. TTE exhibits in the popliteal vein higher increases of PVV compared to MPE. Trial registration: Trial_ID: ISRCTN49260430. Date: 11/01/2022. Retrospectively registered.

Place, publisher, year, edition, pages
Springer, 2023
Keywords
Electric stimulation therapy, Hemodynamics, Motor point, NMES, Pain, Textile electrodes
National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:hb:diva-30255 (URN)10.1007/s00421-023-05212-5 (DOI)000982776600001 ()2-s2.0-85158166949 (Scopus ID)
Available from: 2023-08-15 Created: 2023-08-15 Last updated: 2024-02-21Bibliographically approved
Juthberg, R., Flodin, J., Guo, L., Rodriguez, S., Persson, N.-K. & Ackermann, P. W. (2023). Neuromuscular electrical stimulation in garments optimized for compliance. European Journal of Applied Physiology
Open this publication in new window or tab >>Neuromuscular electrical stimulation in garments optimized for compliance
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2023 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327Article in journal (Refereed) Published
Abstract [en]

Purpose

Physical inactivity is associated with muscle atrophy and venous thromboembolism, which may be prevented by neuromuscular electrical stimulation (NMES). This study aimed to investigate the effect on discomfort, current amplitude and energy consumption when varying the frequency and phase duration of low-intensity NMES (LI-NMES) via a sock with knitting-integrated transverse textile electrodes (TTE).

Methods

On eleven healthy participants (four females), calf-NMES via a TTE sock was applied with increasing intensity (mA) until ankle-plantar flexion at which point outcomes were compared when testing frequencies 1, 3, 10 and 36 Hz and phase durations 75, 150, 200, 300 and 400 µs. Discomfort was assessed with a numerical rating scale (NRS, 0–10) and energy consumption was calculated and expressed in milli-Joule (mJ). Significance set to p ≤ 0.05.

Results

1 Hz yielded a median (inter-quartile range) NRS of 2.4 (1.0–3.4), significantly lower than both 3 Hz with NRS 2.8 (1.8–4.2), and 10 Hz with NRS 3.4 (1.4–5.4) (both p ≤ .014). Each increase in tested frequency resulted in significantly higher energy consumption, e.g. 0.6 mJ (0.5–0.8) for 1 Hz vs 14.9 mJ (12.3–21.2) for 36 Hz (p = .003). Longer phase durations had no significant effect on discomfort despite generally requiring significantly lower current amplitudes. Phase durations 150, 200 and 400 µs required significantly lower energy consumption compared to 75 µs (all p ≤ .037).

Conclusion

LI-NMES applied via a TTE sock produces a relevant plantar flexion of the ankle with the best comfort and lowest energy consumption using 1 Hz and phase durations 150, 200 or 400 µs.

Place, publisher, year, edition, pages
Springer, 2023
Keywords
Electric stimulation therapy, Pain, Patient comfort, Patient compliance
National Category
Textile, Rubber and Polymeric Materials
Research subject
Textiles and Fashion (General)
Identifiers
urn:nbn:se:hb:diva-29837 (URN)10.1007/s00421-023-05181-9 (DOI)000982817500001 ()2-s2.0-85165608495 (Scopus ID)
Funder
Vinnova, 2019-05479Karolinska Institute
Available from: 2023-05-25 Created: 2023-05-25 Last updated: 2024-02-01Bibliographically approved
Dutta, S., Mehraeen, S., Martinez, J. G., Bashir, T., Persson, N.-K. & Jager, E. W. H. (2023). Textile Actuators Comprising Reduced Graphene Oxide as the Current Collector. Macromolecular materials and engineering
Open this publication in new window or tab >>Textile Actuators Comprising Reduced Graphene Oxide as the Current Collector
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2023 (English)In: Macromolecular materials and engineering, ISSN 1438-7492, E-ISSN 1439-2054Article in journal (Refereed) Epub ahead of print
Abstract [en]

Electronic textiles (E-textiles) are made using various materials including carbon nanotubes, graphene, and graphene oxide. Among the materials here, e-textiles are fabricated with reduced graphene oxide (rGO) coating on commercial textiles. rGO-based yarns are prepared for e-textiles by a simple dip coating method with subsequent non-toxic reduction. To enhance the conductivity, the rGO yarns are coated with poly(3,4-ethylene dioxythiophene): poly(styrenesulfonic acid) (PEDOT) followed by electrochemical polymerization of polypyrrole (PPy) as the electromechanically active layer, resulting in textile actuators. The rGO-based yarn actuators are characterized in terms of both isotonic displacement and isometric developed forces, as well as electron microscopy and resistance measurements. Furthermore, it is demonstrated that both viscose rotor spun (VR) and viscose multifilament (VM) yarns can be used for yarn actuators. The resulting VM-based yarn actuators exhibit high strain (0.58%) in NaDBS electrolytes. These conducting yarns can also be integrated into textiles and fabrics of various forms to create smart e-textiles and wearable devices. 

Keywords
actuator, e-textiles, graphene oxide, strain, viscose multifilament, viscose rotor spun
National Category
Textile, Rubber and Polymeric Materials Materials Chemistry
Research subject
Textiles and Fashion (General)
Identifiers
urn:nbn:se:hb:diva-31025 (URN)10.1002/mame.202300318 (DOI)001108784700001 ()2-s2.0-85178101670 (Scopus ID)
Funder
EU, Horizon 2020, 825232Promobilia foundation, A21029Familjen Erling-Perssons Stiftelse, 2020‐0054
Available from: 2023-12-14 Created: 2023-12-14 Last updated: 2024-01-17Bibliographically approved
Flodin, J., Wallenius, P., Guo, L., Persson, N.-K. & Ackermann, P. (2023). Wearable Neuromuscular Electrical Stimulation on Quadriceps Muscle Can Increase Venous Flow. Annals of Biomedical Engineering, 51(12), 2873-2882
Open this publication in new window or tab >>Wearable Neuromuscular Electrical Stimulation on Quadriceps Muscle Can Increase Venous Flow
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2023 (English)In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 51, no 12, p. 2873-2882Article in journal (Refereed) Published
Abstract [en]

Neuromuscular electrical stimulation (NMES) of the quadriceps (Q) may increase venous blood flow to reduce the risk of venous thromboembolism. This study assessed whether Q-NMES pants could increase peak venous velocity (PVV) in the femoral vein using Doppler ultrasound and minimize discomfort. On 15 healthy subjects, Q-NMES using textile electrodes integrated in pants was applied with increasing intensity (mA) until the first visible muscle contraction [measurement level (ML)-I] and with an additional increase of six NMES levels (ML II). Discomfort using a numeric rating scale (NRS, 0–10) and PVV were used to assess different NMES parameters: frequency (1, 36, 66 Hz), ramp-up/-down time (RUD) (0, 1 s), plateau time (1.5, 4, and 6 s), and on:off duty cycle (1:1, 1:2, 1:3, 1:4). Q-NMES pants significantly increased PVV from baseline with 93% at ML I and 173% at ML II. Frequencies 36 Hz and 66 Hz and no RUD resulted in significantly higher PVV at both MLs compared to 1 Hz and 1 s RUD, respectively. Plateau time, and duty cycle did not significantly change PVV. Discomfort was only significantly higher with increasing intensity and frequency. Q-NMES pants produces intensity-dependent 2−3-fold increases of venous blood flow with minimal discomfort. The superior NMES parameters were a frequency of 36 Hz, 0 s RUD, and intensity at ML II. Textile-based NMES wearables are promising for non-episodic venous thromboembolism prevention. 

Keywords
Electrical stimulation therapy, Muscle stimulation, Skeletal muscles, Thromboprophylaxis, Deep vein thrombosis, Venous thromboembolism, Peak venous velocity, Textile electrodes, Smart textiles
National Category
Materials Engineering
Identifiers
urn:nbn:se:hb:diva-31335 (URN)10.1007/s10439-023-03349-0 (DOI)001050737400001 ()2-s2.0-85168343519 (Scopus ID)
Funder
Swedish Research Council, 2017-00202Stockholm County Council, SLL20180348Karolinska Institute
Available from: 2024-01-16 Created: 2024-01-16 Last updated: 2024-02-01Bibliographically approved
Huniade, C., Melling, D., Vancaeyzeele, C., Nguyen, T.-M. G., Vidal, F., Plesse, C., . . . Persson, N.-K. (2022). Ionofibers: Ionically Conductive Textile Fibers for Conformal i-Textiles. Advanced Materials Technologies
Open this publication in new window or tab >>Ionofibers: Ionically Conductive Textile Fibers for Conformal i-Textiles
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2022 (English)In: Advanced Materials Technologies, E-ISSN 2365-709XArticle in journal (Refereed) Published
Abstract [en]

With the rise of ion-based devices using soft ionic conductors, ionotronics show the importance of matching electronic and biological interfaces. Since textiles are conformal, an essential property for matching interfaces, light-weight and comfortable, they present as an ideal candidate for a new generation of ionotronics, i-textiles. As fibers are the building blocks of textiles, ionically conductive fibers, named ionofibers, are needed. However, ionofibers are not yet demonstrated to fulfill the fabric manufacturing requirements such as mechanical robustness and upscaled production. Considering that ionogels are known to be conformal films with high ionic conductivity, ionofibers are produced from commercial core yarns with specifically designed ionogel precursor solution via a continuous dip-coating process. These ionofibers are to be regarded as composites, which keep the morphology and improve the mechanical properties from the core yarns while adding the (ionic) conductive function. They keep their conductivity also after their integration into conformal fabrics; thus, an upscaled production is a likely outlook. The findings offer promising perspectives for i-textiles with enhanced textile properties and in-air electrochemical applications.

Keywords
bioelectronic interfaces, ionic conductivity, ionogels, ionotronics, textile fibers
National Category
Textile, Rubber and Polymeric Materials
Research subject
Textiles and Fashion (General)
Identifiers
urn:nbn:se:hb:diva-27917 (URN)10.1002/admt.202101692 (DOI)000799031200001 ()2-s2.0-85130425979 (Scopus ID)
Projects
WEAFING
Funder
EU, Horizon 2020, 825232
Available from: 2022-05-24 Created: 2022-05-24 Last updated: 2022-09-19
Dutta, S., Mehraeen, S., Persson, N.-K., Martinez, J. G. & Jager, E. W. .. (2022). The effect of electroactive length and intrinsic conductivity on the actuation behaviour of conducting polymer-based yarn actuators for textile muscles. Sensors and actuators. B, Chemical, 370, Article ID 132384.
Open this publication in new window or tab >>The effect of electroactive length and intrinsic conductivity on the actuation behaviour of conducting polymer-based yarn actuators for textile muscles
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2022 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 370, article id 132384Article in journal (Refereed) Published
Abstract [en]

Recently, electrically driven conducting polymer (CP) coated yarns have shown great promise to develop soft wearable applications because of their electrical and mechanical behaviour. However, designing a suitable yarn actuator for textile-based wearables with high strain is challenging. One reason for the low strain is the voltage drop along the yarn, which results in only a part of the yarn being active. To understand the voltage drop mechanism and overcome this issue intrinsically conductive yarns were used to create a highly conductive path along the full length of the yarn actuator. Ag plated knit-de-knit (Ag-KDK) structured polyamide yarns were used as the intrinsically conductive core material of the CP yarn actuators and compared with CP yarn actuators made of a non-conductive core knit-de-knit (KDK) yarn. The CP yarn actuators were fabricated by coating the core yarns with poly(3,4-ethylene dioxythiophene): poly(styrene sulfonic acid) followed by electrochemical polymerization of polypyrrole. Furthermore, to elucidate the effect of the capillarity of the electrolyte through the yarn actuator, two different approaches to electrochemical actuation were applied. All actuating performance of the materials were investigated and quantified in terms of both isotonic displacement and isometric developed forces. The resultant electroactive yarn exhibits high strain (0.64 %) in NaDBS electrolytes as compared to previous CP yarn actuator. The actuation and the electroactivity of the yarn were retained up to 100 cycles. The new highly conductive yarns will shed light on the development of next-generation textile-based exoskeleton suits, assistive devices, wearables, and haptics garments.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Actuator, Yarn, Knit-de-knit, PEDOT: PSS/PPy, Strain, Force
National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:hb:diva-28968 (URN)10.1016/j.snb.2022.132384 (DOI)000881475400002 ()2-s2.0-85135912639 (Scopus ID)
Funder
Promobilia foundation, F17603EU, Horizon 2020EU, Horizon Europe, 825232Linköpings universitet, 2009-00971Familjen Erling-Perssons Stiftelse
Available from: 2022-11-23 Created: 2022-11-23 Last updated: 2022-11-24Bibliographically approved
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