Herein, we report a biofriendly, air-operating electrochemical platform based on a unipolar coiled carbon nanotube (CNT) yarnartificial muscle that can operate either as an ionic actuator or as an ionotronic strain sensor. The device comprises two coiled CNTyarn electrodes coated with complementary ion-selective eutectogels, consisting of fixed-charge polymer networks swollen witha diluted deep eutectic solvent (DES), enabling selective ion transport. Under an applied potential difference, the complementaryelectrochemical responses of both electrodes produce synchronized unipolar contraction, whereas in sensing mode the devicegenerates a strain-dependent open-circuit voltage (OCV) variation. In actuation mode, the device achieves a maximal reversiblecontractile stroke of 2.9% under a 90 mN pre-load. In sensing mode, it operates as a self-powered strain sensor with a sensitivityof 0.5 mV.%−1 . Poisson–Nernst–Planck modelling is consistent with the proposed mechanism of strain-induced ion redistributionwithin the quasi-solid-state matrix. Two yarn artificial muscles were woven into a custom-made, bi-stretch auxetic structure witha folded zigzag geometry, enabling parallel actuation and strain monitoring, delivering peak-to-peak OCV signals of 4 mV at 10%extension. Finally, we demonstrate a wireless wearable armband for real-time motion monitoring, highlighting the potential ofthis platform for smart fabrics, wearable electronics, and adaptive soft robotics.

Our research found that the shedding of microplastic fibers (MPFs) from textiles is exacerbated by repeated mechanical recycling, raising environmental concerns as the use of recycled fibers increases in industry. This study examined MPF release from fabrics containing 30% mechanically recycled polyester fibers subjected to one, two, or three recycling cycles, compared to primary (virgin) polyester (PES). Shedding was assessed under both simulated wear and laundering conditions using Martindale, ICI Pilling Box, and ISO 4484–1:2023 (microplastic from textile sources) protocols. Laundering tests showed no clear difference in MPF release between primary PES and once-recycled PES (rPES-1; ∼ 1.4-fold). In contrast, fabrics with fibers recycled twice (rPES-2) and three times (rPES-3) released about 4.3-fold and 6.2-fold more MPFs than PES, respectively. Fiber release was different under dry-state abrasion than in laundry tests, highlighting the limitations of current wet-state focused assessments. Progressive fiber fragmentation and increased yarn hairiness suggest cumulative structural degradation with each recycling cycle. These findings underscore the need for standardized dry-state shedding assessments and improved recycling strategies to mitigate MPF emissions. While mechanical recycling remains environmentally preferable to uncontrolled disposal, these findings reveal a trade-off in the form of increased MPF release after multiple recycling cycles, which could be mitigated through improved recycling processes and fabric design. Achieving a balance between textile circularity and environmental sustainability remains a critical challenge for the industry.

Soft actuators based on conducting polymer coated yarns and textiles are promising for wearable applications. Nevertheless, improving the mechanical performance of yarn actuators for practical wearable applications remains a challenge. Coiling techniques have been utilized to enhance the performance of conducting polymer–based yarn actuators. To illustrate their potential for in-air applications, a double coiled yarn actuator was designed and characterized in this work. While coiled yarn actuators generally perform well in liquid electrolytes, achieving stable and high-performance actuation in air remains a significant challenge. A typical double coiled yarn actuator consists of two coiled yarns, each coated with doped conducting polymers, connected via an ionogel that serves as the ion reservoir. The yarn actuator demonstrated an initial isotonic strain of approximately 0.3% and generated an isometric force of around 2.5 mN in air. These results underscore the critical role of redox reactions happening at conducting polymers and ionic transport mechanisms in enabling efficient actuation in air and provide a framework for advancing scalable, wearable electroactive textile actuator technologies.

Soft robotics employs deformable materials and structures to achieve compliance and adaptability, enabling safe and close interaction with humans. Merging electromechanically active polymer actuation with textile technology enables soft, large area actuators with form factors being 1D (fibers), 2D (fabrics), or 3D (garments), all relevant for wearable soft robotics. This study investigates in-air actuating polypyrrole (PPy)-based trilayer tape yarns (TYs) and the effect of integrating them into woven fabric actuators. Individual TYs are developed, consisting of two polypyrrole layers sandwiching a poly(vinylidene fluoride) (PVDF) membrane filled with anionic liquids (IL). The impact of ionic liquid, PPy thickness, and frequency response on displacement and blocking force is investigated. Individual TYs offer the highest displacement of 30.6 ± 3.6 mm (±1.5 V) at 2.5 mHz and blocking force at 0.20 ± 0.07 mN (±1.0 V, 2.5 mHz). Next, weaving is used to integrate TYs into plain weave actuating fabrics, enabling the assembly of many TYs together without a decrease in displacement. Additive force in woven actuators scales linearly with increased force up to 1.13 ± 0.18 mN (5 TYs), addressed by integrated conductive yarns. Multiarea fabric actuation is demonstrated, as well as an on-body wearable application of the fabric actuator.

Advances in combining soft electromechanically active polymers with textiles at the fibre and yarn levels of the textile hierarchy contribute to the development of textile actuators or, by borrowing terms from physiology, of textile muscles. Textile muscle fibres, made by continuous electropolymerisation of pyrrole (Py) onto polyamide 6/6 multifilaments coated with poly(3-4-ethylenedioxythiophene) (PEDOT), are able to perform shortening, isometric, and lengthening contractions in liquid electrolytes and withstand the fabric manufacturing processes. To date, the contractile performance in liquid electrolytes of these textile muscle fibres, dependent on electrochemically driven volume change, has yet to be translated to in air as part of a fabric. Therefore, textile muscle fibres are explored as a fundamental unit of textile muscles together with ionofibres for their innervation. Ionofibres, continuously produced by UV polymerisation of ionogel precursors onto the surface of polyamide 6/6 multifilaments, are used to interlace closely with the textile muscle fibres and act as ion source/sink during the electrochemical processes. Their close contacts in a fabric enable the textile muscle fibres to contract in air under electrical stimuli. Regarding the ionofibres, two ionogels based on either 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIm⁺OTf⁻) entrapped in a polythioether network or choline acetate (Chol⁺OAc⁻) entrapped in a poly(2-hydroxyethyl methacrylate) network are explored. All the different produced fibres are evaluated individually in terms of electrical conductivity, tensile properties, and, for the textile muscle fibres, contractile properties. The investigation of the contractile properties includes repeated stimuli of yarn samples in individual warp rib structures with multiple signal frequencies and shapes. This contribution evaluates textile muscle fibres during contractions in air within a weave, representing for such fibres the first demonstration of actuation in ambient air. Beyond this milestone, the study seeks to identify critical manufacturing bottlenecks that limit realistic applications, establishing a foundation for developing practical textile muscles through standardised characterisation.

Reliable evaluation of affective responses is essential in haptic research, yet it remains unclear whether commonly used self-report tools provide comparable results given differences in scale format and representation. Therefore, this study investigated how three self-report tools, Visual Analog Scale (VAS) sliders, Numerical Rating Scales (NRS) and the EmojiGrid assess emotional experiences in response to two text-based haptic scenarios. Eighty-nine participants completed an anonymous survey in which valence and arousal were rated using all three tools. Quantitative analyses examined score differences, association and agreement between measures. User likings were explored using both rating data and open-ended questions. The results showed substantial overlap between valence ratings obtained by VAS and NRS, although these measures were not fully interchangeable. The scores obtained using the EmojiGrid showed overall higher scores across both scenarios for both valence and arousal, with arousal showing no monotonic relationship and poor agreement. User reported likings for a particular reporting tool did not significantly influence emotional ratings, suggesting that observed differences are more likely misinterpretation rather than preference bias. Qualitative feedback indicated that participants appreciated the visual and expressive nature of the EmojiGrid but reported confusion regarding its axis, emojis and midpoint. The higher EmojiGrid scores may partly result from the use of a discrete grid rather than its original continuous scale, which could have inflated ratings and reduced measurement precision. Overall, this study provides insights into the design and use of emotional self-report tools for haptic research. 

Electrotactile stimulation can evoke a wide range of sensations, including taps, squeezes, and strokes. Although verbal descriptors are available for vibrotactile and ultrasound stimuli, a comprehensive list has not been developed for electrotactile experiences. To address this, we used a text normalization approach to generate descriptors for wearable electrotactile research and design. In Experiment 1 (N=14), Dutch participants provided 504 open-ended descriptions in response to 36 electrotactile stimuli on the forearm. These were processed into 71 unique English descriptors with considerable inter-rater reliability. Experiment 2 (N=24) evaluated a reduced list of 42 descriptors under additional stimulation conditions, showing robust and consistent descriptor usage, also across varying stimulus intensities. This list partially overlaps with previous non-electrotactile descriptor lists but also includes terms that seem to be unique to electrotactile sensations. Altogether, our findings contribute to the development of common verbal descriptors for electrotactile stimulation, supporting future wearable haptic research and design.

The continuous production of textile muscle fibres made by continuous electropolymerisation of polypyrrole (PPy) onto multifilaments coated with poly(3,4-ethylenedioxythiophene) (PEDOT) and of surface ionofibres made by UV coating ionogels on commercial multifilaments enables the manufacturing of textile muscles. Here, plain woven fabrics combining textile muscle fibres as warp threads and ionofibres as weft threads are investigated. This study aims to understand the translation of the contractile properties of textile muscle fibres in aqueous sodium dodecylbenzenesulphonate (NaDBS) to the behaviour of the fibres in such woven fabrics. Indeed, in a plain weave, the contact of the textile muscle fibres with an ion source/sink is only done at the interlacings with the ionofibres. Compared to crude fabric coatings, this contribution opens up to a new generation of textile muscles.

This study evaluated the hemodynamic effects, discomfort, and energy efficiency of low-intensity neuromuscular electrical stimulation (LI-NMES) of the calf delivered via sock-integrated transverse textile electrodes (TTE) at different frequencies and plateau times. Fifteen healthy participants underwent NMES stimulation through 3 × 3 cm TTE with ten combinations of frequency (1–36 Hz) and plateau times (0.5–7 s). NMES was increased until plantar flexion occurred, at which point ultrasound-measurements were made of popliteal peak venous velocity (PVV), time-averaged mean velocity (TAMV), average duration of blood flow pulse (ADBP) and ejection volume (EV). Discomfort (NRS, 0–10), current amplitude, and energy consumption were recorded. Median values were analyzed with significance set at p < 0.05. Both 1 Hz and 36 Hz C-LI-NMES significantly improved PVV and TAMV (p ≤ 0.008). EV increased significantly for plateau times of 1.5, 5.0, and 7.0 s (p < 0.05). Compared to 36 Hz, 1 Hz showed significantly lower discomfort (NRS: 0.4 vs. 1.6) and energy consumption (0.4 vs. 31.3 mJ, both p ≤ 0.01) but required higher current amplitude (33.2 vs. 23.3 mA, p < 0.01) to reach plantar flexion. The study concludes that both 1 Hz and 36 Hz frequency improve venous hemodynamics, but 1 Hz stimulation minimizes discomfort and energy use while maintaining effectiveness.

Technological solutions for use by persons with deafblindness, helping to navigate the environment, and communicate with it independently of human assistants, have been developed in different areas of research. Some achievements are used already, are under development, or are produced for other purposes. This chapter reviews technology addressing the navigation needs of persons with deafblindness presented in academic research. The authors deal with haptic navigation and textile-related devices potentially suitable for persons with deafblindness, e.g., hand-held and hands-free devices, robot guide dogs, textiles and wearables enriched with sensors, and effectors as enablers. Sensor and actuation technologies underpinning these devices are presented for better understanding of their functionality. The main directions of the development and the level of the prototype or product, its potential for targeted users, and availability of devices are identified in the text. The text includes conceptual clarifications of the explored technologies and the summary of identified research directions.