Scalable Wood Hydrogel Membrane with Nanoscale Channels

Area of Science:

• Materials Science
• Nanotechnology
• Sustainable Energy

Background:

• Developing large-scale nanofluidic materials with controlled nanochannels is challenging.
• Existing materials often lack robustness and tunable properties for applications like water purification and energy generation.

Purpose of the Study:

• To demonstrate a scalable and cost-effective method for fabricating a robust nanofluidic wood hydrogel membrane.
• To investigate the ion transport properties and energy harvesting capabilities of the fabricated membrane.

Main Methods:

• Infiltrating a poly(vinyl alcohol)/acrylic acid (PVA/AA) hydrogel into the natural bimodal porous structure of balsa wood.
• Characterizing the mechanical strength and ionic conductivity of the resulting wood hydrogel membrane in both radial (R) and longitudinal (L) directions.
• Evaluating the membrane's performance in harvesting electrical energy from salinity gradients.

Main Results:

• The wood hydrogel membrane exhibited 3 times higher strength (52.7 MPa) compared to natural balsa.
• Ionic conductivity was significantly enhanced (2 orders of magnitude higher), reaching 1.29 mS cm^-1 (L-direction) and ~1 mS cm^-1 (R-direction) at low salt concentrations.
• A current density of up to 17.65 μA m^-2 and power density of 0.56 mW m^-2 were achieved from salinity gradients, improvable to 2.7 mW m^-2 with increased AA content.

Conclusions:

• The fabricated wood hydrogel membrane offers a scalable, cost-effective, and robust platform for nanofluidic applications.
• The material demonstrates significant potential for energy harvesting from salinity gradients using sustainable wood resources.
• This work contributes to the development of advanced nanofluidic devices and sustainable energy solutions.