Textile actuators based on coiled yarns coated with conductive polymers aregaining increasing attention for wearable applications. Coiled yarn actuators showsuperior performance due to the geometrical and mechanical effects of the coils.A typical configuration to use coiled yarn actuators in air consists of two coiledyarns coated with different conductive polymers, connected through an ionogel.One coiled yarn actuator is cation-driven, while the other is anion-driven, ensuringsynchronized actuation strains. Although coiled yarn actuators generally showhigh actuation performance in electrolytes, developing a high performance, andstable yarn actuator that works effectively in air remains a challenge for manyapplications. In this study, we employed a step-by-step approach to systematicallyidentify the limitations affecting actuation in a double coiled yarn actuator. First,each coiled yarn actuator was individually characterized in a three-electrodeelectrochemical system in an electrolyte. Next, the performance of the individualcoiled yarns was evaluated in presence of an anion-driven coiled yarn as counterelectrode. In the third step, the system was studied in a two-electrode system, andfinally, the overall performance was assessed in air using an ionogel. This studyoffers important insights into the working principles of double coiled yarnactuators and establishes the foundation for optimized designs of such actuatorsin air applications.

In the fabrication of textile-based ionic EAP actuators, yarns are first coated with PEDOT by solution dip coating to make the passive yarns conductive. This is followed by PPy deposition to induce electrochemicaldrivenactuation. In these textile-based actuators, the performance of the actuators depends amongst others on the mechanical and electrical properties of the first conductive PEDOT coating layer. In this study 5different PEDOT solutions were prepared by adding different additives to poly(3,4-ethylenedioxythiophene) polystyrene sulfonate solutions. Films were formed from these solutions and their electrical conductivityand mechanical strength were measured. These solutions were then coated on polyamide multifilament yarns and dried at different temperatures, and their resistance and mechanical properties were measured. Theyarn coated with PEDOT:PSS-PG 90 weight percent exhibit the lowest Young's modulus 0.33 MPa at room temperature, while the yarn coated with PEDOT:PSS-PEG-DMSO exhibited the lowest resistance of 130 ohms at180°C. This study provides valuable insights that by tailoring the PEDOT solution composition and drying temperature the conductivity and mechanical properties of the coated yarn can be improved ultimatelypaving the way for better actuation performance of the textile-based ionic EAP actuators.

Smart textile actuators are gaining attention for applications in soft robotics and wearable electronics. These actuators can undergo controlled, reversible deformation in response to external stimuli like temperature changes or electric potential. Recent advancements focus on integrating smart yarns, fibre actuators, and functional materials directly in/on textiles. The mechanics of the textile substrate influence the actuation performance of these devices, which can enable complex movements. By using different weave patterns in combination with different yarns, the mechanical anisotropy of the substrate can be enhanced. Additive manufacturing offers a promising approach for fabricating these actuators, allowing rapid customization of active and passive material patterns. This study explores multi-layered PEDOT:PSS actuators 3D-printed onto various textile substrates via syringe-based extrusion. The effects of different weave patterns on bending actuation are examined, and the findings highlight the relationship between textile design, material composition, and fabrication methods in optimizing smart textile actuators.

Smart textile actuators have garnered increasing attention owing to their versatile applications in soft robotics and wearable electronics. These actuators exhibit the capability to undergo controllable and reversible deformation in response to external stimuli such as temperature variations or electric potential. The latest evolution in smart textiles involves the integration of smart yarn- and fiber-actuators, as well as the incorporation of smart materials onto textile substrates. The underlying mechanics of the textile substrate play a significantrole in determining the overall performance of these actuators, offering opportunities to achieve intricate actuation modes effectively.

Moreover, the utilization of additive manufacturing techniques presents a promising avenue for the fabrication of these devices, enabling rapid customization and optimization of both active and passive material patterns to amplify their functionality. In this investigation, multi-layered PEDOTactuators were 3D printed on different textile fabrics using syringe-based extrusion, with the aim of investigating how different weave and knit patterns influenced actuation performance. Additionally, intricate patterns of passive materials were incorporated through printing methods, leveraging distributed compliance to program the movement capabilities of the actuators. This work sheds light on the interplay between textile substrate design, material composition, and fabrication techniques in enhancing the performance and functionality of smart textile actuators.

Intelligent fiber-elastomer composites and intelligent textiles are both active research areas in the fields of soft robotics and wearables. Tailored properties for these applications can be obtained by tailoring textile structures and fiber functionalities, such as integrated sensor or actuator properties. This work focuses on developing filamentary conductive polymer actuators for use in soft robotics or wearables. The actuators are based on wet-spun poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) fibers, with Polypyrrole (PPy) electropolymerized onto the PEDOT:PSS fibers surface. By varying the duration of PPy electropolymerization, and thus the thickness of the PPy coating, this study investigates its effect on the mechanical and actuation properties of the fibers. The developed actuator fibers achieve a repeatable high linear contractile elongation of up to 1.7%, tensile forces of about 100 mN, and mechanical stresses of about 1 MPa. Such properties make these fibers a compelling choice as a base material for textiles to be integrated into soft robotics and wearables.

Smart Textile is a branch of functional textiles with a built-in ability to respond to various stimuli like chemicals, light, or electricity. The key component of these textiles is “smart yarn” which is engineered to respond the external stimuli. Traditionally, smart textiles focused on textile-based sensors. Now the focus is shifting to the development of yarn and fabric actuators. Yarn coated with poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrole (PPy) acts like a soft actuator. When these smart yarns exposed to an electrochemical potential, the PPy coating contracts and expands, like an artificial muscle.  The thickness of the PPy coating impacts the actuator’s performance. A thicker coating can generate greater force but might be less responsive (slower contraction/expansion). This paper investigates the effect of PPy thickness on the performance of yarn actuators. The passive yarns were dip-coated with a conductive Poly-3,4-ethylenedioxythiophene: Polystyrene sulfonate (PEDOT: PSS), Dimethyl sulfoxide (DMSO) and polyethylene glycol 400 (PEG 400) mixture to make them electrically conductive yarns. Then PPy with different thicknesses were deposited using an electro-polymerization process. The resulting yarn actuators were then evaluated for three key properties: strain, speed of movement, and force generation, using a lever arm setup.

Smart textile actuators have been of growing interest due to their applications in soft robotics, exoskeletons, and assistive garments, and can deform controllably and reversibly under application of an external stimulus such as temperature or electric potential. This next generation of smart textiles integrate smart yarn and fiber actuators, and/or the deposition of smart materials in/on textile substrates. The mechanics of the textile substrate used for these actuators has an effect on the performance of the devices, and can be used advantageously to achieve complex actuation modes. Additionally, additive manufacturing processes can be used to fabricate the actuators, providing a means to quickly modify and adapt the patterning of both active and passive materials to further enhance performance. In this study, multi-layered PEDOT:PSS actuators were 3D printed on different woven textiles via syringe-based extrusion to explore the effects of the weave pattern on actuation performance. Furthermore, passive materials were printed in different patterns, utilizing selective compliance to program the movement capabilities of the devices