Patterned surface with controllable wettability for inkjet printing of flexible printed electronics

Area of Science:

• Materials Science
• Surface Engineering
• Nanotechnology

Background:

• Inkjet printing is a versatile technique for fabricating electronic devices.
• Achieving high-resolution printing of conductive inks requires precise control over substrate surface properties.
• Existing methods often struggle with controlling wettability for complex patterns.

Purpose of the Study:

• To investigate novel methods for creating patterned surfaces with combined hydrophilic and hydrophobic properties.
• To demonstrate the effectiveness of these patterned surfaces for high-resolution inkjet printing.
• To improve the printing quality of fine resolution structures using controlled surface wettability.

Main Methods:

• Fabrication of patterned surfaces using a two-step coating process with 3-aminopropyl trimethoxysilane (APTMS) and a 3M electronic grade chemical on PET surfaces.
• Selective hydrophilic treatment of specific regions using atmospheric O2/Ar plasma or UV/ozone treatment with a Nickel stencil.
• Characterization of surface wettability using water contact angle (WCA) measurements.
• Inkjet printing of PEDOT/PSS conductive ink on the patterned surfaces.

Main Results:

• Creation of surfaces with distinct hydrophobic regions (WCA ~105°) and superhydrophilic regions (WCA <5°).
• Selective wetting of PEDOT/PSS conductive ink, with ink spreading along hydrophilic areas and avoiding hydrophobic regions.
• Successful inkjet printing of fine features smaller than the droplet size (~55 μm) due to high wettability contrast.

Conclusions:

• Controlled surface wettability is crucial for improving inkjet printing resolution and quality.
• The developed two-step coating and selective treatment method effectively creates patterned surfaces for precise ink deposition.
• This approach offers a viable strategy for fabricating microscale conductive patterns using inkjet printing.