Spatial control of curing kinetics in thiol-ene-systems through antagonistic photoreactions

Area of Science:

• Polymer Chemistry
• Photochemistry
• Materials Science

Background:

• Two-wavelength photochemistry offers precise control over resin curing.
• Thiol-ene photopolymerization is a versatile reaction for material synthesis.

Purpose of the Study:

• To investigate wavelength orthogonal photochemistry for spatial control of thiol-ene polymerization.
• To demonstrate antagonistic photochemical control for sub-micron patterning.

Main Methods:

• Utilized a resin system comprising pentaerythritol-tetrakis(3-mercaptopropionat) (PETMP) and triallyl-triazine-2,4,6(1H,3H,5H)-trione (TATO).
• Activated radical curing with a type II photoinitiator at 450 nm.
• Inhibited curing by photoreleasing a base at 365 nm.

Main Results:

• Achieved antagonistic photochemical control in thiol-ene polymerization.
• Demonstrated laser writing with minimum feature sizes below 0.5 µm.
• Successfully performed grey scale patterning experiments.

Conclusions:

• Spatially controlled inhibition and retardation of thiol-ene curing on a sub-micron scale are feasible.
• This technique has potential applications in advanced large area lithography, including interference lithography.