D. Schönfeld,1 T. Galambos,1 D. Chalissery,1 A.-L. Poser,1 K. Temme,1 M. Walter,2 C. Teicht,2 and T. Pretsch1

1 Fraunhofer Institute for Applied Polymer Research IAP, Geiselbergstraße 69, 14476 Potsdam, Germany; dilip.chalissery@iap.fraunhofer.de; dennis.schoenfeld@iap.fraunhofer.de; theodor.galambos@iap.fraunhofer.de; anna-lisa.poser@iap.fraunhofer.de; kerim.temme@iap.fraunhofer.de; thorsten.pretsch@iap.fraunhofer.de

2 Fraunhofer Institute for Chemical Technology ICT, Joseph-von-Fraunhofer-Straße 7, 76327 Pfinztal, moritz.walter@ict.fraunhofer.de; christian.teicht@ict.fraunhofer.de

Shape memory polymers are a class of smart materials. Among them, thermoplastic polyurethanes are probably the best studied today. Thermoplastic polyurethanes can be synthesized with a wide variety of properties. Control over the thermally triggerable one-way shape memory effect is possible through both chemical formulation and a thermomechanical treatment known as programming. One-way shape memory effects offer advantages in security labels to protect against counterfeiting [1] and for monitoring cold chains [2] as well as in foil-guided dentistry (orthodontic aligners).[3]

Recently, the rapidly growing knowledge base in two-way programming of shape memory polymers has led to new types of actuators and helped to open up the field of research on programmable materials. The approach of programming system functionalities associated with programmable materials enables a paradigm shift in product design, as it aims to simplify technological complexity - the functionality is now in the material or component. Bidirectional actuating polymers have particular potential for use as actuators in soft robotics, [4] as self-regulating energy systems [5] and in the field of intelligent façade technologies.[6]

The contribution provides insights into the synthesis, processing and programming of polyurethanes with shape memory properties and highlights promising technological developments that open up new design possibilities from an application perspective.

Financial support from Fraunhofer Cluster of Excellence Programmable Materials, grant number 40-06514-2500-00021, is kindly acknowledged. Further financial support was received from the European Union (EFRE, project 85007031 and ProFIT Brandenburg, ILB, project 85062983) and from Federal Ministry for Economic Affairs and Climate Action (projects 20400 BR and KK5392602NK2).

References

[1] T. Pretsch, M. Ecker, M. Schildhauer, M. Maskos, J Mater Chem 2012, 22, 7757-7766.

[2] N. Fritzsche, T. Pretsch, Macromolecules 2014, 47, 5952-5959.

[3] D. Schönfeld, S. Koss, N. Vohl, F. Friess, D. Drescher, T. Pretsch, materials 2023, 16, art. no. 3094.

[4] D. Schönfeld, D. Chalissery, F. Wenz, M. Specht, C. Eberl, T. Pretsch, Molecules 2021, 26, art. no. 522.

[5] D. Schönfeld, M. Walter, C. Teicht, M. Walter, T. Rümmler, T. Pretsch, Smart Mater Meth 2024, 1-27.

[6] M. Walter, F. Friess, M. Krus, S. M. H. Zolanvari, G. Grün, H. Kröber, T. Pretsch, Polymers 2020, 12, art. no. 1914.