Triple and Quadruple Surface Pattern Memories in Nanoimprinted Polymer Blends

Area of Science:

• Materials Science
• Polymer Science
• Surface Engineering

Background:

• Trigger-responsive surfaces offer diverse applications, but achieving multiple, controllable surface memories remains challenging.
• Existing shape-memory effects in bulk polymers have limitations in programming and recovering multiple surface topographies.
• Controlled surface morphological changes are key to developing advanced functional surfaces.

Purpose of the Study:

• To achieve multiple micro-topography memories in polymer surfaces through controlled fabrication.
• To investigate the synergy between polymer blend formulation and thermal nanoimprinting for multi-memory surfaces.
• To enhance the elastic properties of polymer blends for improved pattern fixity and recovery.

Main Methods:

• Utilizing immiscible blends of poly(caprolactone) (PCL) and polyethylene (PE) with distinct thermal transitions.
• Augmenting blend elasticity through preferential cross-linking with dicumyl peroxide.
• Employing thermal nanoimprinting to create and recover multiple surface patterns.

Main Results:

• Demonstrated triple and quadruple surface pattern fixity and recovery in nanoimprinted PCL/PE blends.
• Successfully recovered a micropillar structure from a hierarchical micrograting topography using a thermal stimulus (60 °C for 180 s).
• Showcased sequential recovery of a deformed micrograting followed by a micropillar structure.

Conclusions:

• The synergy between polymer blend formulation and thermal nanoimprinting enables the creation of surfaces with multiple, programmable shape memories.
• Preferential cross-linking significantly enhances the elastic properties of PCL/PE blends, crucial for pattern recovery.
• This approach paves the way for advanced trigger-responsive surfaces with complex, recoverable topographies for various applications.