Madalena Pereira

Synthesis of poly(3, 4-ethylenedioxythiophene) coating on textiles by the vapor phase polymerization method

In this article, plain weave fabrics of polyester were functionalized by means of a polymeric coating synthesized for high conductivity, using the vapor phase polymerization method. The method is considerably more efficient and sustainable than traditional wet methods and has been previously applied to synthesize poly(3, 4-ethylenedioxythiophene) in yarns and fabrics, using oxidant agents with organic solvents. In this article, aqueous oxidant solutions were used in addition to those based in ethanol, providing textile substrates with high electrical conductance. The effect of the concentration of the oxidant solution on the electrical and mechanical characteristics of the samples was investigated and correlated to their morphology, analyzed by electron microscopy imaging. A strong decrease of the sheet resistivity of the samples with the concentration of oxidant increase was obtained, while the fabrics’ original mechanical tenacity remained unchanged. The sheet resistivity of the samples could be further decreased by a factor of 5 by the application of multiple polymerization layers and was a function of the conjugated polymer content. The effect of washing/drying cycles on the electrical conductance of the samples is presented. The electrical and mechanical characteristics obtained have potential for smart textile applications such as electromagnetic shielding and physiological sensing.

Design and Evaluation of Novel Textile Wearable Systems for the Surveillance of Vital Signals

This article addresses the design, development, and evaluation of T-shirt prototypes that embed novel textile sensors for the capture of cardio and respiratory signals. The sensors are connected through textile interconnects to either an embedded custom-designed data acquisition and transmission unit or to snap fastener terminals for connection to external monitoring devices. The performance of the T-shirt prototype is evaluated in terms of signal-to-noise ratio amplitude and signal interference caused by baseline wander and motion artefacts, through laboratory tests with subjects in standing and walking conditions. Performance tests were also conducted in a hospital environment using a T-shirt prototype connected to a commercial three-channel Holter monitoring device. The textile sensors and interconnects were realized with the assistance of an industrial six-needle digital embroidery tool and their resistance to wear addressed with normalized tests of laundering and abrasion. The performance of these wearable systems is discussed, and pathways and methods for their optimization are highlighted.

Digital printing techniques for denim jeans

This chapter discusses the technological possibilities of using inkjet printing in the development of digital denim. It begins with an overview of current state of the art solutions in digital textile printing and makes a comparison with the traditional techniques of denim colouration, printing and finishing. There follow the essentials of textile printing and colour management, addressing raster image processing issues as well as topics related to image manipulation techniques. Finally, techniques for developing digital denim and some practical applications in clothing design are discussed.