文档介绍:Abstract Traditional shape memory polymers (SMPs) are those capable of memorizing a temporary shape and recovering to the permanent shape upon heating. Although such a basic concept has been known for half a century, recent progresses have challenged the conventional understanding of the polymer shape memory effect and significantly expanded the practical potential of SMPs. In this article, notable recent advances in the field of SMPs are highlighted. Particular emphasis is placed on how the new developments have changed the conventional view of SMPs, what they mean for practical applications, and where the future opportunities are. Graphical abstract Keywords Shape memory polymer; Stimuli-responsive polymer; Polymer actuator 1. Introduction Shape memory polymers (SMPs) represent a technologically important class of stimuli-responsive materials for which the response lies in the shape change. More specifically, the conventional definition of an SMP isa polymer can be deformed and subsequently fixed into a temporary shape, which would remain stable unless it is exposed to an appropriate external stimulus that triggers the polymer to recover to its original (or permanent) shape. Accordingly, the associated behavior of SMP is called polymer shape memory effect (SME). Although various forms of external stimuli may be utilized as the recovery trigger, the most typical one is direct