Effect of Stitch Pattern on the Electrical Properties of Wale-wise Knitted Strain Sensors and Interconnects

Chia, Pei Zhi; Gupta, Ujjaval; Tan, Ying Yi; Lau, Jun Liang; Ahmed, Alvee; Soh, Gim Song; Low, Hong Yee

doi:10.1109/sensors47087.2021.9639732

Cited by 3 publications

(3 citation statements)

References 13 publications

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“…Both interconnects and resistors need fixed resistances, but resistors should have high resistance while interconnects should have the lowest resistance possible. [ 51 ] We achieved these vastly different electromechanical responses within the same conductive fabric by optimizing the yarn composition and stitch type in each component's stitch pattern, as discussed below. For knitting terminology definitions, please refer to Note S1 and Figure S1 (Supporting Information).…”

Section: Development and Fabrication Of Highly Stretchable Knitted El...mentioning

confidence: 99%

All Knitted and Integrated Soft Wearable of High Stretchability and Sensitivity for Continuous Monitoring of Human Joint Motion

Gupta

Lau

Chia

et al. 2023

Adv Healthcare Materials

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E‐textiles have recently gained significant traction in the development of soft wearables for healthcare applications. However, there have been limited works on wearable e‐textiles with embedded stretchable circuits. Here, stretchable conductive knits with tuneable macroscopic electrical and mechanical properties are developed by varying the yarn combination and the arrangement of stitch types at the meso‐scale. Highly extensible piezoresistive strain sensors are designed (>120% strain) with high sensitivity (gauge factor 8.47) and durability (>100,000 cycles), interconnects (>140% strain) and resistors (>250% strain), optimally arranged to form a highly stretchable sensing circuit. The wearable is knitted with a computer numerical control (CNC) knitting machine that offers a cost effective and scalable fabrication method with minimal post‐processing. The real‐time data from the wearable is transmitted wirelessly using a custom designed circuit board. In this work, an all knitted and fully integrated soft wearable is demonstrated for wireless and continuous real‐time sensing of knee joint motion of multiple subjects performing various activities of daily living.

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Section: Development and Fabrication Of Highly Stretchable Knitted El...mentioning

confidence: 99%

All Knitted and Integrated Soft Wearable of High Stretchability and Sensitivity for Continuous Monitoring of Human Joint Motion

Gupta

Lau

Chia

et al. 2023

Adv Healthcare Materials

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“…Our study, therefore, aims to bridge this gap by focusing on the fundamental effects of basic stitches (knit and purl) and the interaction between conductive and non-conductive yarns. Elucidating these basics is expected to make a key contribution to the development of more complex stitch patterns in plated knit sensor designs [ 31 , 32 ].…”

Section: Introductionmentioning

confidence: 99%

Assessing the Role of Yarn Placement in Plated Knit Strain Sensors: A Detailed Study of Their Electromechanical Properties and Applicability in Bending Cycle Monitoring

Kim,

Jun,

et al. 2024

Sensors

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In this study, we explore how the strategic positioning of conductive yarns influences the performance of plated knit strain sensors fabricated using commercial knitting machines with both conductive and non-conductive yarns. Our study reveals that sensors with conductive yarns located at the rear, referred to as ‘purl plated sensors’, exhibit superior performance in comparison to those with conductive yarns at the front, or ‘knit plated sensors’. Specifically, purl plated sensors demonstrate a higher sensitivity, evidenced by a gauge factor ranging from 3 to 18, and a minimized strain delay, indicated by a 1% strain in their electromechanical response. To elucidate the mechanisms behind these observations, we developed an equivalent circuit model. This model examines the role of contact resistance within varying yarn configurations on the sensors’ sensitivity, highlighting the critical influence of contact resistance in conductive yarns subjected to wale-wise stretching on sensor responsiveness. Furthermore, our findings illustrate that the purl plated sensors benefit from the vertical movement of non-conductive yarns, which promotes enhanced contact between adjacent conductive yarns, thereby improving both the stability and sensitivity of the sensors. The practicality of these sensors is confirmed through bending cycle tests with an in situ monitoring system, showcasing the purl plated sensors’ exceptional reproducibility, with a standard deviation of 0.015 across 1000 cycles, and their superior sensitivity, making them ideal for wearable devices designed for real-time joint movement monitoring. This research highlights the critical importance of conductive yarn placement in sensor efficacy, providing valuable guidance for crafting advanced textile-based strain sensors.

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“…In the case of 1 × 1 rib knitted samples, the effect of the aspect ratio and shape of the sensing region was evaluated by Raji et al and they concluded that plain rectangular sensors showed higher repeatability and lower noise levels compared to non-rectangular shaped sensors [ 15 ]. A 1 × 1 rib knit design was found to be promising as a strain sensor and presented a sensor with a GF of 1.36 and a working range of 0–21% by Chia et al [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

Development of Low Hysteresis, Linear Weft-Knitted Strain Sensors for Smart Textile Applications

Bozali

Ghodrat

Plaude

et al. 2022

Sensors

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In recent years, knitted strain sensors have been developed that aim to achieve reliable sensing and high wearability, but they are associated with difficulties due to high hysteresis and low gauge factor (GF) values. This study investigated the electromechanical performance of the weft-knitted strain sensors with a systematic approach to achieve reliable knitted sensors. For two elastic yarn types, six conductive yarns with different resistivities, the knitting density as well as the number of conductive courses were considered as variables in the study. We focused on the 1 × 1 rib structure and in the sensing areas co-knit the conductive and elastic yarns and observed that positioning the conductive yarns at the inside was crucial for obtaining sensors with low hysteresis values. We show that using this technique and varying the knitting density, linear sensors with a working range up to 40% with low hysteresis can be obtained. In addition, using this technique and varying the knitting density, linear sensors with a working range up to 40% strain, hysteresis values as low as 0.03, and GFs varying between 0 and 1.19 can be achieved.

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Effect of Stitch Pattern on the Electrical Properties of Wale-wise Knitted Strain Sensors and Interconnects

Cited by 3 publications

References 13 publications

All Knitted and Integrated Soft Wearable of High Stretchability and Sensitivity for Continuous Monitoring of Human Joint Motion

All Knitted and Integrated Soft Wearable of High Stretchability and Sensitivity for Continuous Monitoring of Human Joint Motion

Assessing the Role of Yarn Placement in Plated Knit Strain Sensors: A Detailed Study of Their Electromechanical Properties and Applicability in Bending Cycle Monitoring

Development of Low Hysteresis, Linear Weft-Knitted Strain Sensors for Smart Textile Applications

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