Multifunctional, Bioinspired, and Moisture Responsive Graphene Oxide/Tapioca Starch Nanocomposites

Abstract

Actuators triggered by water evaporation have found potential applications in a wide range of emerging fields, including smart structures, power generators, artificial muscles, and soft robots. In addition to poor mechanical performance, conventional actuators raise major economic and environmental concerns due to their expensive and complex synthesis processes with hazardous chemicals and high ecological footprint. Herein, a nacre‐inspired moisture‐responsive actuator is fabricated using graphene oxide (GO) and tapioca starch (TS), a water‐soluble, low‐cost, and eco‐friendly natural polymer. The resultant TS/GO nanocomposite film has excellent mechanical properties and exhibits rapid and autonomous locomotion under moisture attack. Moreover, the actuator demonstrates a bending speed of ≈60° s−1 and has the potential to lift a load up to ten times its own weight. Based on these features, a novel moisture detection alarm system with control and operating circuits is assembled using the TS/GO film. Furthermore, the TS/GO actuator shows that it is capable of mimicking biological structures like flowers and can undergo locomotion even for nonwater vapors like isopropyl alcohol, ethanol, and chloroform.

Robust and Highly Sensitive Cellulose Nanofiber-Based Humidity Actuators

“…Most remarkably, the CNF/GO/CNT composite film’s exceptional humidity-responsive performance in terms of response time and recovery time, along with excellent cycle stability and desirable mechanical properties, allows it to outperform previously reported humidity-responsive actuators (Figure f, Table S1). − ,− …”

Multistimulus-Responsive Graphene Oxide/Fe3O4/Starch Soft Actuators

“…Moreover, the symmetric and asymmetric −CH 2 stretching peaks have shifted to lower wavenumbers of 2876 and 2922 cm –1 , respectively. Therefore, these shifts in peak positions confirm that the polymer matrix and nanofillers are assembled via inter/intramolecular hydrogen bonds. , …”

“…Therefore, these shifts in peak positions confirm that the polymer matrix and nanofillers are assembled via inter/intramolecular hydrogen bonds. 37,38 The thermal stability of the GO, Fe 3 O 4 , TS, and TFG nanocomposites is investigated by thermogravimetric analysis (TGA). As shown in Figure 3b, the pristine GO sheets experience two major mass loss domains between 110−210 and 420−560 °C, which are associated with the removal of oxygen-containing functional groups and pyrolysis of carbon.…”

Green flexible electronics based on starch

“…It is also known as electronic nose 79,[93][94][95] . Starch can be used to tune the nanostructure of gas sensor to enhance its sensitivity and selectivity 96 . Kumar et al 97 investigated the use of amylose and amylopectin functionalized carbon nanotubes (CNT) to fabricate electronic noses on microelectrodes by spraying them layer by layer to detect vapors of water, methanol and toluene.…”