The status of textile-based dry EEG electrodes

Electroencephalogram (EEG) is the biopotential recording of electrical signals generated by brain activity. It is useful for monitoring sleep quality and alertness, clinical applications, diagnosis, and treatment of patients with epilepsy, disease of Parkinson and other neurological disorders, as well as continuous monitoring of tiredness/ alertness in the field. We provide a review of textile-based EEG. Most of the developed textile-based EEGs remain on shelves only as published research results due to a limitation of flexibility, stickability, and washability, although the respective authors of the works reported that signals were obtained comparable to standard EEG. In addition, nearly all published works were not quantitatively compared and contrasted with conventional wet electrodes to prove feasibility for the actual application. This scenario would probably continue to give a publication credit, but does not add to the growth of the specific field, unless otherwise new integration approaches and new conductive polymer composites are evolved to make the application of textile-based EEG happen for bio-potential monitoring

PEDOT:PSS/PDMS-coated cotton fabric for strain and moisture sensors

In this work, we have successfully developed a flexible, lightweight, and washable strain and moisture sensor textile fabric by printing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate/polydimethylsiloxane-b-polyethylene oxide (PEDOT:PSS/PDMS) conductive polymer composite on knitted cotton fabric. A 60.2 kΩ/sq surface resistance has been obtained at a 30% ratio of PDMS to PEDOT:PSS at 0.012 g/cm2 solid add-on. The coated fabric was washed at 30 °C for 30 min in the presence of a standard detergent. It was observed that there was a 5.3% increase in surface resistance, i.e., 63.4 kΩ/sq. After coating, the fabric could still be stretched up to the infliction elongation of the fabric, i.e., 40%, with a significant change in surface resistance that makes it usable as a strain sensor. In addition, the conductive fabric showed a drop in surface resistance with an increase of the moisture regain up to 150%

Surface modification of polyester using chicken feather keratin hydrolysate to improve water absorbency and dye uptake

PET fiber has an intrinsic low hydrophilic character and an inactive surface which make it uncomfortable for wearing purpose. Moreover, it is difficult to colour polyester fabric other than disperse dyes. Therefore, surface modification of PET is very important to improve its absorbency and bring the possibility to dye polyester with anionic dyes by altering its surface characteristics. This research was focused on surface modification of polyester using chicken feather which involves serine as the most abundant amino acid with hydroxyl groups. The treated polyester fabric using 20ml/L concentration of chicken feather extract showed improved water drop absorbency from 45 into 3 seconds and the reactive dye uptake by 36 folds from 0.15 to 5.37 K/S values