Printable cellulose-based electroconductive composites for sensing elements in paper electronics

Abstract

Conductive flexible hydrogel composites were printed on paper substrates using a functional ink, which was designed and formulated for screen-printing. The inks were prepared using abundant and eco-friendly materials by blending carbon fibers into the matrix of a water-soluble cellulose derivative, carboxymethyl cellulose. For an optimal concentration of carbon fibers (10 wt.%), the printed patterns exhibit a sheet resistance of around 300 Ω/sq without any post-printing annealing process. The resistance of the screen-printed hydrogel patterns is sensitive to variations of relative air humidity through moisture adsorption and swelling of the cellulosic matrix surrounding the carbon fibers. It was found that the sensitivity to temperature and humidity can be triggered by drying the printed patterns at 120 °C. A negative temperature coefficient thermistor with a sensitivity of 0.079 °C−1 at 25 °C and a hygristor, where a variation in the RH from 10% to 60% increases the resistance by 15 times, were screen-printed on paper using the formulated cellulose/carbon fibers based ink.

Evaluation of the Sheet Resistance of Inkjet-Printed Ag-Layers on Flexible, Uncoated Paper Substrates Using Van-der-Pauw’s Method

“…Additionally, barrier layers or so-called "pre-coatings" might be required to separate the top coating from the paper substructure. For this purpose, resins [28], polyethylene [26] or other polymer-based materials [25] are used. Despite the obvious advantages of coating, it is an additional time-and resource-consuming processing step that increases the resulting material price.…”

Humanoid Robot Actuation through Precise Chemical Sensing Signals

“…The advantage of wireless passive LC sensors is that it enables efficient detection of signals wirelessly without using additional power sources like batteries . Cellulose‐based materials have been developed and utilized to make eco‐friendly flexible sensors . The LC printed with the cellulose‐based conductive ink of this study has its merits of being disposable, biocompatible, and eco‐friendly.…”

Wide range humidity sensors printed on biocomposite films of cellulose nanofibril and poly(ethylene glycol)

“…The high specific surface caused by the ultrafine 3D BC network structure greatly enhanced the overall sensitivity of the sensor. Beside simple pouring or casting cellulose-based films on a carrier substrate, Barras et al 55 prepared conductive printing ink by blending carbon fibers (CFs) in the CMC. Wang et al 49 demonstrated the application of cellulose nanocrystals (CNCs) as a component in conductive composite based on hybridized nanocarbons.…”

“…Hashim and Hadi 52 published a new type of cellulose nanocomposite with titanium carbide (TiC) nanoparticles, while Chani et al 53 fabricated humidity sensor based on cellulose acetate (CA) composite with copper oxide (CuO) nanosheets and Ma et al 54 mixed hydroxyethyl cellulose (HEC) with multiwalled carbon nanotubes (MWCNTs) to form humidity sensing composite film on a ceramic substrate. Beside simple pouring or casting cellulose-based films on a carrier substrate, Barras et al 55 prepared conductive printing ink by blending carbon fibers (CFs) in the CMC. This was then used for screenprinting of humidity sensing elements on paper.…”