Exploring the Shift From 3-D Printing to 4-D Printing: A Review

The advent of 3-D printing has revolutionized industries, while 4-D printing introduces dynamic shape changes over time, driven by materials programmed to respond to stimuli autonomously. This advancement represents a significant leap in additive manufacturing, with wide-ranging implications across various fields. Consequently, this study serves as a comprehensive resource for readers aiming to understand the current state of 3-D and 4-D printing technologies. It seeks to elucidate research patterns and recent trends through an analysis of a dataset obtained from the Scopus database. The scientometric analysis yields valuable insights into the geographical distribution of authors, publication trends, country collaborations, and cocitation networks. These analyses identify the most prolific researchers, track temporal developments, highlight leading collaborative nations, and delineate prominent research trends within this domain. The results indicate that emerging research areas include "shape memory polymer (SMP)," "continuous fiber," "freeform surface," "self-healing hydrogel," and multimaterial and eco-friendly materials advancements are emerging research areas. Furthermore, we conducted a systematic literature review to extract critical insights, identify research challenges, and propose future research directions within this dynamic field.