Polymers are not only versatile materials, they also can be equipped with functions like electrical conductivity or the ability to actively move. The shape-memory effect (SME) is the ability of a polymer to recover a memorized shape when it is exposed to a suitable stimulus. The SME is based on the combination of a suitable polymer network architecture, which is formed by three components: permanent netpoints, temporary netpoints, and chain segments, as well as a programming process.
Shape-memory polymers (SMP) have a great potential for different fields of applications. Each application demands a complex combination of properties and functions. To meet all the requirements, tailored polymers have to be synthesized.
Now, in a new publication, Andreas Lendlein and colleagues (Helmholtz-Zentrum Geesthacht, Teltow, and University of Potsdam) discuss the main synthetic challenges of designing SMPs and introduce a modular system as a type of “construction manual” for SMPs. The chemistry of permanent netpoints, temporary netpoints, and chain segments is explained which, for example, enables the use of various stimuli or besides the SME itself allows the implementation of additional functions such as biodegradability. Furthermore, different approaches for polymer architectures are explained which form the basis for triple- and multi-shape materials that can perform two or more consecutive shape changes.
By individual combination of the modular components, the foundation for future developments of multifunctional and stimuli-sensitive SMPs is laid.