Photo-cross-linking: A powerful and versatile strategy to develop shape-memory polymers

Shape-memory polymers (SMPs), as an important class of smart materials, have been attracting interests from both academia and industries. Over the past two decades, the fundamental principles of SMPs have been well established, facilitating research to design different types of SMPs at the molecular structure level. Meanwhile, in recent years, increasing attention has been paid to design SMPs with unique shape memory behavior and manufacture SMP articles with sophisticated shape towards practical applications. Notably, photo-cross-linking strategy has actively established a powerful platform to develop SMPs from basic molecular structure design to advanced design and manufacturing. This review emphasizes the view that there is a close connection between photo-cross-linking strategy and SMPs. Following a brief introduction on the important general aspects of SMPs, progress in research on various photo-cross linking approaches used for molecular structure design of SMPs is reviewed. To depict the significance of photo-cross-linking strategy for SMPs beyond conventional molecular structure design, achievements at unconventional aspects of advanced design and 4D printing are highlighted. (C) 2019 Elsevier B.V. All rights reserved.