After being severely and quasi-plastically distorted, shape memory materials (SMMs) are able to recover their original shape at the presence of the right stimulus. In recent years we have seen significant progress from shape memory alloys (SMAs) to shape memory polymers (SMPs). In this paper, we summarize the most recent advances in SMMs. The focus is on the new features found in traditional SMMs, namely SMAs and SMPs, and a newly emerging type of SMM, namely shape memory hybrid (SMH), which enables enthusiasts to design SMMs with tailored properties/features for a particular application without the aid of experts (“do-it-yourself” manner).

We demonstrate the new features of a polyurethane shape memory polymer: water-driven actuation and recovery in sequence (i.e., programmable). Hydrogen bonding is identified as the reason behind these features. In addition, the absorbed water is quantitatively separated into two parts, namely, the free water and bound water. Their individual contribution on the glass transition temperature is identified.