A surface charge governed nanofluidic diode based on a single polydimethylsiloxane (PDMS) nanochannel

Area of Science:

• Nanoscience and Nanotechnology
• Materials Science
• Electrochemistry

Background:

• Nanofluidic diodes are crucial for controlling ion flow at the nanoscale.
• Current designs often use complex materials like carbon nanotubes or membranes.
• Developing PDMS-based nanofluidic diodes is desirable for easier integration into electronic systems.

Purpose of the Study:

• To create a high-performance nanofluidic diode using a single polydimethylsiloxane (PDMS) nanochannel.
• To investigate the effect of surface modification with polyelectrolytes on nanochannel properties.
• To achieve efficient ion gating and current rectification.

Main Methods:

• Fabrication of a nanofluidic diode by modifying a single PDMS nanochannel.
• Utilizing layer-by-layer (LBL) deposition of charged polyelectrolytes, specifically Polybrene (PB) and Dextran sulfate (DS).
• Controlling nanochannel size and generating asymmetric surface charges at the channel ends.

Main Results:

• The developed nanofluidic diode exhibits high effective current rectification.
• Achieved a record rectification ratio of 218 in PB/DS modified nanochannels.
• Rectification ratio is sensitive to voltage frequency, ionic concentration, and nanochannel length.

Conclusions:

• Surface modification of PDMS nanochannels with polyelectrolytes is a viable strategy for creating high-performance nanofluidic diodes.
• The achieved rectification ratio surpasses previous records for similar systems.
• This approach offers a promising pathway for developing integrated nanofluidic devices for on-chip applications.