A Switchable and Compressible Carbon Nanotube Sponge Electrocapillary Imbiber

Abstract

Carbon nanotube sponges are lightweight, conductive, highly porous, and flexible. An integration of these properties is suitable for constructing high-performance electrocapillary imbibers. Water imbibition into the sponges can be initiated at low potentials with tunable uptake rates and switched on and off reversibly. These controllable nanoporous imbibers have potential applications in a wide range of flexible micro- and nanofluidic systems.

3D Self‐Supporting Porous Magnetic Assemblies for Water Remediation and Beyond

“…Recently, some electrical conductive 3D-SPMAs have been prepared by either using conductive 3D networks or imparting additional conductive components. [9,127] Once the electrical conductivity is introduced, the magnetic properties could be modulated by applying external voltage, and some interesting properties might appear. The marriage of magnetism with special optical, thermal, and other physicochemical properties might also be beneficial for both fundamental studies and novel applications.…”

Oriented Graphene Foam with Tunable Wettability by Electrocapillary for Switchable and Ultra‐Fast Imbibition

“…Meanwhile, its surface wettability can be reversibly switched and the imbibition rate can be readily modulated by controlling the applied potential. Thanks to its large pore sizes and much less tortuous channels (Figure b), this OGF showed an extremely high dynamic rate of imbibition (3.0 mg s −1/2 mm −2 ) at −0.9 V. This value is more than triple those of the graphene foam with a disordered pore structure (DGF, 0.89 mg s −1/2 mm −2 ) and CNT sponge (0.80 mg s −1/2 mm −2 ) at the same potential . The average imbibition rate of OGF (0.347 mg s −1 mm −2 ) is even 100 times larger than that of the switchable imbiber made of porous Au sponge (3.5 µg s −1 mm −2 ) …”

“…Dynamic rates, D , can be obtained by the linear fitting of m − t 1/2 curves (Figure c, and Figure S15, Supporting Information). For OGF, its dynamic rate was measured to be zero at the potentials between 0 and −0.2 V. It gradually increased to 0.23 mg s −1/2 mm −2 at −0.3 V and then dramatically increased to 2.41 mg s −1/2 mm −2 at −0.6 V. Finally, D increased slowly to 3.0 mg s −1/2 mm −2 as the potential was negatively changed from −0.6 to −0.9 V. In comparison, the maximum D of OGF at −0.9 V is more than triple those of DGF (0.89 mg s −1/2 mm −2 ) and previously reported CNT sponges (0.80 mg s −1/2 mm −2 ) at the same potential . Additionally, the average imbibition rate for OGF until the saturation was calculated to be 0.347 mg s −1 mm −2 ; this value is even two orders of magnitude larger than the switchable imbiber based on a porous Au sponge (3.5 µg s −1 mm −2 ) …”

“…On the basis of this phenomenon, a variety of applications have been explored; examples include fluidic control, variable lenses, electronic papers, and mechanical‐to‐electrical energy conversion . Recently, nanoporous gold (NG) and carbon nanotube (CNT) sponges have been used to control the imbibition of electrolytes into these sponges at low operating potentials (e.g., 1 V). However, in these systems, the imbibition rates were low, mainly due to the small pore sizes and tortuous microstructures of these materials.…”

Encoding Smart Microjoints for Microcrawlers with Enhanced Locomotion

“…Material is crucial for the design of microrobots, which regulates their mechanical properties and further determines their functions. Smart materials, which can sense and react to external stimuli, such as temperature, pH, light, humidity, magnetism, and electric fields, are indispensable for fabricating untethered soft microrobots. However, almost all stimuli–response materials reported exclusively exhibit a monotonic dependence of swelling deformation with some specific stimulus.…”