Transparent and Flexible Cellulose Nanocrystal/Reduced Graphene Oxide Film for Proximity Sensing

Abstract

The rapid development of touch screens as well as photoelectric sensors has stimulated the fabrication of reliable, convenient, and human-friendly devices. Other than sensors that detect physical touch or are based on pressure sensing, proximity sensors offer controlled sensibility without physical contact. In this work we present a transparent and eco-friendly sensor made through layer-by-layer spraying of modified graphene oxide filled cellulose nanocrystals on lithographic patterns of interdigitated electrodes on polymer substrates, which help to realize the precise location of approaching objects. Stable and reproducible signals generated by keeping the finger in close proximity to the sensor can be controlled by humidity, temperature, and the distance and number of sprayed layers. The chemical modification and reduction of the graphene oxide/cellulose crystal composite and its excellent nanostructure enable the development of proximity sensors with faster response and higher sensitivity, the integration of which resolves nearly all of the technological issues imposed on optoelectronic sensing devices.

Superb adsorption capacity of biochar derived from leather shavings for Congo red

“…4b) indicate stretching vibration of O-H of biochar before adsorption and N-H of CR, respectively. 51,52 The peak of biochar-CR was broadened, which indicated that hydrogen bonds form between the O-H groups of biochar and the -NH 2 groups of CR. 13 In other words, CR adsorption on LSB occurs via chemical adsorption.…”

Emerging flexible and wearable physical sensing platforms for healthcare and biomedical applications

“…The tunability of the physical properties of these nanomaterials is one of the promising features for their implementation as versatile sensing platforms 72,73 . Indeed, graphene-based physical sensors have been demonstrated in many applications in recent years, including the detection and monitoring of humidity 74 , pH 75 , chemicals 76,77 , biomolecules 73,[78][79][80] , and mechanical forces [81][82][83] . Moreover, the biocompatibility of graphene opens up further possibilities for its use as a fundamental element of implantable biophysical sensors.…”

“…They also incorporate solid-state components that function as their active sensing elements. To date, a majority of these solid-state sensing elements are made of various polymer-, carbon-, and metallic conductor-based nanomaterials, such as polymer nanofibers 23,24,32 , silver (Ag) and gold (Au) nanoparticles and nanowires 3,37,98 , CNTs [29][30][31] , and graphene [81][82][83]99 . Solid-state nanomaterials have been deemed a suitable candidate for flexible conductors because they possess unique physical properties, including a high aspect ratio, superior electrical conductivity and mechanical strength, and low density.…”

Conductive Elastomers with Autonomic Self‐Healing Properties

“…Similar phenomena also were observed in ac ellulose nanocrystal/reduced graphene oxide film. [43] These observations were attributed to the electrically conducting nature of the human body.T he skin tissue displays ac ertain electric field, as the finger comes closer to the surface of the sensor material, and the fringe electric field produced by the material is disturbed because of at iny electric charge transfer from the finger,inducing fluctuations in the resistance. [43][44][45][46] This human skin recognition capacity of PHEMA-SWCNT composites makes them good candidates for smart robotics.…”