Implementing and Quantifying the Shape-Memory Effect of Single Polymeric Micro/Nanowires with an Atomic Force...

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Current methods for shape-memory effect (SME) in micro/nano-objects use indirect macroscopic techniques.
• These methods are applied to ensembles of objects, limiting individual analysis.

Purpose of the Study:

• To introduce a method for controlled manipulation and SME quantification of individual micro- and nano-objects.
• To enable thermomechanical testing analogous to macroscopic procedures.

Main Methods:

• Utilized an atomic force microscope (AFM) to manipulate individual electro-spun poly(ether urethane) (PEU) micro/nanowires.
• Freely suspended wires between micropillars on a silicon substrate for testing.

Main Results:

• Achieved programming strains of 10±1% and 21±1% with successful fixation.
• Observed near-complete shape restoration upon heating, confirming excellent SME.
• Measured apparent recovery stresses of 1.2±0.1 MPa (microwire) and 33.3±0.1 MPa (nanowire).

Conclusions:

• The developed AFM platform allows for precise implementation and quantification of SME in individual polymeric micro/nanosystems.
• This method provides a universal approach for studying thermomechanically induced functions at the nanoscale.