Shape memory of a polymer grating surface fabricated by two-beam interference lithography

Area of Science:

• Materials Science
• Optics
• Polymer Science

Background:

• Switchable and reversible optical elements are crucial for self-adaptive optics.
• Shape-memory polymers offer adaptive properties controllable by environmental or field stimuli.

Purpose of the Study:

• To fabricate periodic grating structures in shape-memory polymers using laser interference.
• To demonstrate the memory and recovery of these grating structures, enabling shape-memory functionality.

Main Methods:

• Fabrication of a one-dimensional grating structure using dual-beam interference lithography with a nanosecond laser.
• Application of pressure at 195°C to deform the grating structure.
• Cooling to room temperature to retain the deformed morphology and subsequent heating to 120°C for recovery.

Main Results:

• The grating structure's vertical height was reduced, and diffraction light intensity decreased under pressure at high temperature.
• The deformed grating morphology was successfully preserved upon cooling to room temperature.
• The original grating morphology was recovered upon heating to 120°C, demonstrating the shape-memory effect.

Conclusions:

• Periodic grating structures were successfully fabricated in shape-memory polymers via laser interference lithography.
• The demonstrated shape-memory function of the gratings allows for switchable and reversible optical elements.
• This research paves the way for self-adaptive optical devices utilizing shape-memory polymers.