Studies of Structure and Local Wetting Properties on Heterogeneous, Micropatterned Solid Surfaces by...

Area of Science:

• Polymer Science
• Surface Science
• Materials Science

Background:

• Functionalized polymer patterns are crucial for controlling surface properties.
• Understanding local wettability is key to designing advanced materials.
• Previous methods lacked precision in analyzing complex surface microstructures.

Purpose of the Study:

• To characterize the microstructure and local wettability of photolithographically patterned hairy rod polymers.
• To enhance quantitative reflection interference contrast microscopy (RICM) for improved surface analysis.
• To validate theoretical models of contact angle hysteresis on patterned surfaces.

Main Methods:

• Photolithographic structuring of hairy rod polymer multilayers on glass/MgF2/SiO2 substrates.
• Quantitative reflection interference contrast microscopy (RICM) with improved image analysis accounting for optical and geometrical effects.
• Contact angle measurements of liquid droplets on patterned surfaces to determine surface free energy.
• Analysis of contact angle hysteresis on periodic hydrophobic/hydrophilic domains.

Main Results:

• Developed an enhanced RICM technique for precise microstructure and wettability analysis.
• Determined the surface free energy of hairy rod polymer films.
• Experimental measurements of contact angle hysteresis confirmed theoretical predictions by Joanny and de Gennes.
• Demonstrated the ability to create and analyze periodic hydrophobic/hydrophilic domains.

Conclusions:

• The enhanced RICM method provides accurate quantification of local wettability in patterned polymer films.
• The study validates theoretical models for contact angle hysteresis at patterned interfaces.
• This work offers insights into the surface properties of functionalized hairy rod polymers for material design.