Surface Patterning of Closed Nanochannel Using VUV Light and Surface Evaluation by Streaming Current.

Area of Science:

• Nanofluidics
• Surface Science
• Materials Science

Background:

• Nanospaces are surface-governed due to high surface-to-volume ratios, making surface control critical in nanofluidics.
• Existing surface patterning methods are limited, especially for closed nanochannels.
• Evaluating surface modifications in closed nanochannels lacks appropriate experimental tools.

Purpose of the Study:

• To verify surface patterning in closed nanochannels using vacuum ultraviolet (VUV) light.
• To evaluate the surface modifications using streaming-current measurements.
• To achieve hydrophilic/hydrophobic patterning within nanochannels.

Main Methods:

• Closed nanochannels were modified with C18 groups, confirmed by Laplace pressure measurements.
• Streaming-current measurements were used to evaluate the C18 modification and its decomposition by VUV light.
• VUV light was employed for surface patterning, followed by capillary filling experiments to confirm the patterned interface.

Main Results:

• Successful confirmation of C18 modification in closed nanochannels.
• Streaming-current measurements indicated successful decomposition of C18 groups by VUV light, rendering the surface hydrophilic.
• Demonstrated hydrophilic/hydrophobic patterning within a nanochannel using VUV light.

Conclusions:

• VUV light enables effective surface patterning in closed nanochannels.
• Streaming-current measurements provide a viable method for evaluating surface modifications in closed nanochannels.
• This technique offers precise surface control for advanced nanofluidic applications.