Ivona Jerković

Conductive polymers for smart textile applications

Smart textiles are fabrics able to sense external conditions or stimuli, to respond and adapt behaviour to them in an intelligent way and present a challenge in several fields today such as health, sport, automotive and aerospace. Electrically conductive textiles include conductive fibres, yarns, fabrics, and final products made from them. Often they are prerequisite to functioning smart textiles, and their quality determines durability, launderability, reusability and fibrous performances of smart textiles. Important part in smart textiles development has conductive polymers which are defined as organic polymers able to conduct electricity. They combine some of the mechanical features of plastics with the electrical properties typical for metals. The most attractive in a group of these polymers are polyaniline (PANI), polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) as one of the polythiophene (PTh) derivatives. Commercially available smart textile products where conductive polymers have crucial role for their development are medical textiles, protective clothing, touch screen displays, flexible fabric keyboards, and sensors for various areas. This paper is focused on conductive polymers description, mechanism of their conductivity, and various approaches to produce electrically conductive textiles for smart textiles needs. Commercial products of conductive polymers-based smart textiles are presented as well as the objective of a number of lab-scale items.

Textile Sensors Validatıon to Perform In Situ Structural Health Monitorıng of Textile Reinforced Thermoplastic Composites

Smart textile approach to realize textile sensors compatibility with composite technology is a very promising solution today. Optimisation of sensors need to carry out in order to prepare sensors having negligible affect on reinforcement geometrical and mechanical properties. Weaving of 2D fabrics due to checking the thermo-forming consolidation of textile sensors inserted is an important step to perform in situ structural health monitoring of composites. In this work, E-glass/polypropylene sensors based on poly (3,4-ethylenedioxythiophene)poly (styrenesulfonate) polymer complex were studied. Textile sensors showed resistance to high temperature and pressure by giving electrical resistance responses after 2D textile preforms consolidation and possibility to validate composites developed during tensile loading in situ.

New Textile Sensors for In Situ Structural Health Monitoring of Textile Reinforced Thermoplastic Composites Based on the Conductive Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) Polymer Complex

Many metallic structural and non-structural parts used in the transportation industry can be replaced by textile-reinforced composites. Composites made from a polymeric matrix and fibrous reinforcement have been increasingly studied during the last decade. On the other hand, the fast development of smart textile structures seems to be a very promising solution for in situ structural health monitoring of composite parts. In order to optimize composites’ quality and their lifetime all the production steps have to be monitored in real time. Textile sensors embedded in the composite reinforcement and having the same mechanical properties as the yarns used to make the reinforcement exhibit actuating and sensing capabilities. This paper presents a new generation of textile fibrous sensors based on the conductive polymer complex poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) developed by an original roll to roll coating method. Conductive coating for yarn treatment was defined according to the preliminary study of percolation threshold of this polymer complex. The percolation threshold determination was based on conductive dry films’ electrical properties analysis, in order to develop highly sensitive sensors. A novel laboratory equipment was designed and produced for yarn coating to ensure effective and equally distributed coating of electroconductive polymer without distortion of textile properties. The electromechanical properties of the textile fibrous sensors confirmed their suitability for in situ structural damages detection of textile reinforced thermoplastic composites in real time.

Innovative monitoring of 3D warp interlock fabric during forming process

The final geometry of 3D warp interlock fabric needs to be check during the 3D forming step to ensure the right locations of warp and weft yarns inside the final structure. Thus, a new monitoring approach has been proposed based on sensor yarns located in the fabric thickness. To ensure the accuracy of measurements, the observation of the surface deformation of the 3D warp interlock fabric has been joined to the sensor yarns measurements. At the end, it has been revealed a good correlation between strain measurement done globally by camera and locally performed by sensor yarns.

Global and local observations of 3D warp interlock fabric behaviour during forming process

Forming behaviour of thick 3D fabric leads to unknown locations of yarns inside the 3D warp interlock structure. To check their position, global observation of painted points located at the upper surface with cameras and local measurement of the elongation of inserted sensor yarns have been done simultaneously. Depending on the fabric structure, elongations of yarn reveal the same behaviour as the global structure during the forming process.