4D printing of thermoresponsive materials: a state-of-the-art review and prospective applications

The use of thermoresponsive smart polymers is the need of the hour and a matter of scientific interest in 3D printing applications such as sensors, drug delivery, scaffold manufacturing, tissue engineering, bio-separation, regenerative medicines, and tissue reconstructions. In the last decade, a variety of different thermoresponsive materials and their 3D printing processes have been developed for such applications. So, the novice researchers working in 3D printing of thermoresponsive materials are looking for the collective information of the processing, application, tools, and techniques requirement with future aspects of research. The applications of specific stimuli have been discussed in this paper with their effect on shape change behaviour. This research paper aims to provide state-of-the-art knowledge for the 3D printing of thermoresponsive polymers with knowledge of materials processing, a recent innovation, innovative 3D printing processes used for thermoresponsive materials, materials information of thermoresponsive polymers and targeted applications. The future scope for the 4D printing of thermoresponsive polymers have been provided throughout the manuscript for the extended applications and studies. Also, this study is supported by an innovative case study for the implementation 3D printing process as recycling of thermoresponsive materials for biomedical applications.