Non-woven shape-memory polymer blend actuators

Victor Izraylit,Andreas Lendlein,Karl Kratz,Matthias Heuchel

doi:10.1557/s43580-021-00063-8

Victor Izraylit, Andreas Lendlein + Show 2 more

https://doi.org/10.1557/s43580-021-00063-8

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Journal: MRS Advances	Publication Date: Jun 25, 2021
Citations: 3	License type: open-access

Affiliation: Helmholtz-Zentrum Hereon, University of Potsdam

Abstract

The hierarchical design approach provides various opportunities to adjust the structural performance of polymer materials. Electrospinning processing techniques give access to molecular orientation as a design parameter, which we consider here in view of the shape-memory actuation performance. The aim of this work is to investigate how the reversible strain varepsilon^{prime}_{{{text{rev}}}} can be affected by a morphology change from a bulk material to an electrospun mesh. varepsilon^{prime}_{{{text{rev}}}} could be increased from 5.5 ± 0.5% to 15 ± 1.8% for a blend from a multiblock copolymer with poly(ε-caprolactone) (PCL) and poly(L-lactide) (PLLA) segments with oligo(D-lactide) (ODLA). This study demonstrates an effective design approach for enhancing soft actuator performance, which can be broadly applied in soft robotics and medicine.Graphic abstract

Highlights

Soft polymeric actuators are capable to perform a reversible movement controlled by external stimuli
The physical principle underlying the shape-memory actuation capability is the tendency of polymer molecules in actuator domains to form crystallites along their orientation, which is maintained by a skeleton of a second set of crystallites associated to a higher melting temperature than the actuating crystallites, and their entropy driven contraction upon melting [2]
We have previously demonstrated that blending of a multi-block copolymer containing poly(l-lactide) and poly(ε-caprolactone) segments (PLLA-PCL) with oligo(d-lactide) (ODLA) in a one-step solution-casting process leads to formation of a physical network [13]

Summary

Introduction

Soft polymeric actuators are capable to perform a reversible movement controlled by external stimuli. Tunability and reprogrammability distinguish shape-memory polymer actuators from other types of soft actuators [1]. The physical principle underlying the shape-memory actuation capability is the tendency of polymer molecules in actuator domains to form crystallites along their orientation, which is maintained by a skeleton of a second set of crystallites associated to a higher melting temperature than the actuating crystallites, and their entropy driven contraction upon melting [2]. ′ rev is achieved at the maximal molecular orientation. In a shape-memory polymer actuator, the molecular orientation is typically achieved by deforming the material during the programming procedure. Attempts to achieve higher orientation can lead to disintegrating of the netpoints and disentangling of the network [4, 5]

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