The preparation of graphene/polyethylene oxide/sodium dodecyl sulfate composite humidity sensor via electrohydrodynamic direct-writing

Abstract

Continuous accurate deposition of composites can be achieved by electrohydrodynamic directwriting, but the eddy flow with the Weissenberg effect may affect stable jet, which is important in electrohydrodynamic direct-writing. So electrohydrodynamic direct-writing of micro-scale graphene/polyethylene oxide/sodium dodecyl sulfate composite (the pumping and preparation of graphene composites based on the Weissenberg effect) is studied for the first time. This paper explores the effects on the morphology of graphene composite films such as voltage and collection distance. In addition, the composite is firstly used in a resistance-based humidity sensor. It is found that the composite films are very sensitive to humidity when its width is less than 200 µm due to its porous structure and high specific surface area. When the width of the composite films is about 100 µm, its resistance decreases rapidly as the humidity increases from 63% RH to 100% RH (the response time is less than 2.5 s).

Electrospray: More than just an ionization source

“…The deposits mostly function as electrodes and as such are employed mainly in electronic, photonic, and bioelectronic technologies. Due to the high conductivity, financial availability, and nonoxidizing properties, silver [206–210] colloids are the most frequently used dispersions; however, many other materials are being experimented with as well, for example, gold [211,212], indium tin oxide (ITO) [213], carbon [214,215], and copper [216,217].…”

“…Commonly, the jet breaks into a spray of droplets before coming into contact with the substrate. The resolution of the deposit is, therefore, strongly influenced by the breakup process and should be fully controlled [215]. The substrate is usually mounted on a conductive plate acting as a counter electrode, but the process of focusing the jet can be enhanced by the application of a point electrode and, additionally, a ring electrode [207,211,218].…”

“…Due to the high conductivity, financial availability, and nonoxidizing properties, silver Reprinted with permission from [188]. [206][207][208][209][210] colloids are the most frequently used dispersions; however, many other materials are being experimented with as well, for example, gold [211,212], indium tin oxide (ITO) [213], carbon [214,215], and copper [216,217].…”

Humidity Sensor Based on PEO/PEDOT:PSS Blends for Breath Monitoring

“…[58] This polymer has been mostly tested as a humidity detector through optical [59,60] or impedance/capacitive [61,62] mechanisms, and usually being blended with or coated onto other materials, notably metal oxides and conductive carbon derivatives. [63][64][65][66] Notwithstanding, their ability to interact with and absorb water can furnish outstanding results for the transduction mechanism of chemiresistors. Up to now, there are only a few chemiresistive-based humidity sensors using this polymer [64][65][66] but they are always assembled with inorganic materials such as oxides or graphene.…”

“…[63][64][65][66] Notwithstanding, their ability to interact with and absorb water can furnish outstanding results for the transduction mechanism of chemiresistors. Up to now, there are only a few chemiresistive-based humidity sensors using this polymer [64][65][66] but they are always assembled with inorganic materials such as oxides or graphene. Thus, it lacks a complete organic chemiresistive sensing device for moisture detection with this polymer.…”