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

Abstract

Cellulose nanofibril (CNF) films were prepared from side streams generated by the sugarcane industry, that is, bagasse. Two fractionation processes were utilized for comparison purposes: (1) soda and (2) hot water and soda pretreatments. 2,2,6,6-Tetramethylpiperidinyl-1-oxyl-mediated oxidation was applied to facilitate the nanofibrillation of the bagasse fibers. Poly(ethylene glycol) (PEG) was chosen as plasticizer to improve the ductility of CNF films. The neat CNF and biocomposite films (CNF and 40% PEG) were used for fabrication of self-standing humidity sensors. CNF-based humidity sensors exhibited high change of impedance, within four orders of magnitude, in response to relative humidity (RH) from 20 to 90%. The use of plasticizer had an impact on sensor kinetics. While the biocomposite film sensors showed slightly longer response time, the recovery time of these plasticized sensors was two times shorter in comparison to sensors without PEG. This study demonstrated that agroindustrial side streams can form the basis for high-end applications such as humidity sensors, with potential for, for example, packaging and wound dressing applications.

Nanocellulose-Based Inks—Effect of Alginate Content on the Water Absorption of 3D Printed Constructs

“…It is worth to mention that the hydrophilic nature of CNF, due to its large number of hydroxyl groups on their surface, and the electrical sensitivity of cellulose to water vapor, allows CNF structures to be used as moisture sensor [16,17], which was recently demonstrated for TEMPO CNF [18]. Moreover, moisture balance is especially critical in wound dressings, as excessively moist tissue can lead to maceration and insufficient moisture can lead to drying of the wound, affecting the healing process.…”

Recent advances in 3D printing of nanocellulose: structure, preparation, and application prospects

“…Syrovy et al have explored the printability of CNF/Poly(ethylene glycol) (PEG) biocomposite film for sensing humidity and discussed about the mechanical profile of the printed sensor and its sensory characteristics. 265 The printed CNF-based sensor has responded within 4 orders of magnitude in change of impedance. In addition, the recovery time had been cut half by the integration of PEG plasticizer that facilitate faster desorption of water molecules out of CNF.…”

Ultrasensitive Physical, Bio, and Chemical Sensors Derived from 1‐, 2‐, and 3‐D Nanocellulosic Materials

“…Syrový et al72 prepared self‐standing humidity sensors via directly printing carbon‐based interdigitated electrodes (IDEs) onto CNF/polyethylene glycol (PEG) composite films. The as‐prepared sensors showed a high change of impedance in response to RH from 20% to 90%.…”