Finely Formed, Kinetically Modulated Wrinkle Structures in UV-Crosslinkable Liquid Prepolymers.

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Engineering

Background:

• Wrinkled films possess unique properties like high surface area, beneficial for high-tech applications.
• Current methods using UV-crosslinkable prepolymers typically yield wrinkles in the tens to hundreds of micrometers range.

Purpose of the Study:

• To synthesize a UV-crosslinkable liquid prepolymer capable of forming spontaneous wrinkle structures with micrometer-scale wavelengths.
• To investigate the formation mechanism of these micro-wrinkles, including the simultaneous creation of double layers (hard skin and soft foundation).

Main Methods:

• Synthesis of a novel UV-crosslinkable liquid prepolymer.
• Fabrication of wrinkled films by controlling photoinitiator absorbance and UV-curing conditions.
• Characterization of wrinkle morphology and layer structure.

Main Results:

• Successfully formed spontaneous wrinkle structures with wavelengths in the micrometer range.
• Developed a double-layer structure consisting of a thin hard skin and a soft, contractible foundation.
• Demonstrated that the rate of photo-crosslinking reaction (Rp) influences skin and foundation layer thickness.
• Determined the first-order apparent rate constant (kapp) for wrinkle formation to be between approximately 0.20 and 0.69 s(-1).

Conclusions:

• The developed UV-crosslinkable prepolymer enables the facile fabrication of micro-wrinkled films.
• The wrinkle characteristics, including wavelength and layer thickness, can be effectively modulated by controlling the photo-crosslinking rate (Rp).
• This technique offers a simple and tunable approach for creating advanced wrinkled surfaces for various applications.