Textiles are turning into a suitable next-generation sensing platform because of their good breathability, softness, and structural elasticity. Besides, research on self-powered piezoelectric sensors is a hot topic in wearable applications; they can perform long-term sensing and monitoring. Therefore, this paper mainly reviews the development progress of PVDF-based textiles on flexible piezoelectric sensors. In this paper, we first introduce the principle of the piezoelectric effect and the classification of piezoelectric materials; then we summarize the structure and characteristics of nanofiber mat-based, yarn-based, and fabric-based flexible piezoelectric sensors and the approaches that are employed to fabricate PVDF-based textile piezoelectric sensors such as melt spinning, electrospinning, and stretch forming processes, and so on. At last, we review their applicability in the application of electronic skin, human–computer interaction, healthcare, and human movement monitoring and demonstrate the facing difficulties and the future research directions of PVDF-based textile flexible sensors.

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To realize three-dimensional (3-D) simulation of weft-knitted fabrics, this paper proposes a 3-D loop modeling method which includes yarn texture and rapid deformation of fabric. The deformation of the fabric is achieved using a simplified particle system. In this study, the shape of the loop is controlled by using 10 control points, and the coordinates of the loop type control points are calculated in combination with the actual loop shape and a quadratic Bezier curve equation. To realize the deformation of the loop, the relationship between the control points and the particle system is established. The 3-D surface model of the yarn is constructed based on a local frame of the loop path. In addition, the yarn simulation is achieved by texture mapping. The simulation of fancy weft-knitted fabric is realized by the joint programming of Visual Studio and OpenGL. The results show that the simplified particle model can accurately achieve the deformation of the fabric with high efficiency. The geometric model properly represents the loop shape and exhibits the yarn texture.

In order to create realistic loop primitives suitable for the faster CAD of the flat-knitted fabric, we have performed research on the model of the loop as well as the variation of the loop surface. This paper proposes an interlacing point-based model for the loop center curve, and uses the cubic Bezier curve to fit the central curve of the regular loop, elongated loop, transfer loop, and irregular deformed loop. In this way, a general model for the central curve of the deformed loop is obtained. The obtained model is then utilized to perform texture mapping, texture interpolation, and brightness processing, simulating a clearly structured and lifelike deformed loop. The computer program LOOP is developed by using the algorithm. The deformed loop is simulated with different yarns, and the deformed loop is applied to design of a cable stitch, demonstrating feasibility of the proposed algorithm. This paper provides a loop primitive simulation method characterized by lifelikeness, yarn material variability, and deformation flexibility, and facilitates the loop-based fast computer-aided design (CAD) of the knitted fabric.

With the rapid development of wearable devices, highly sensitive strain sensors with superior flexibility and conductivity are in urgent demand. In this study, a novel 2D and graphene-like material Ti 3 C 2 with excellent electron and ion transmission rates was utilized to decorate electrospinning thermoplastic urethane (ETPU) film for assembling a stretchable strain sensor. The developed ETPU/Ti 3 C 2 sensor exhibits a gauge factor of 2500 kPa −1 in high strain range from 250% to 300%, and 5.2 when the strain <50%, good durability and stability (stretch/release test of 1000 cycles), as well as the distinguishment of various frequencies and strains. Combined with high performance and stable structure, the sensor could be attached on skin or cloths to monitor both subtle and large-scale human motions, such as joint bending and pronunciation. The results demonstrate that the strain sensor has a promising application prospect in artificial skin and wearable health-care electronics.