Advanced 3D/4D Printing for Functional Materials Innovation

摘要

Three-dimensional (3D) printing has established itself as an indispensable tool for the rapid fabrication of intricate physical objects, leveraging the precise translation of digital designs into physical materials. Since the commercialization of the first 3D printer in the early 1980s, this field has witnessed substantial expansion, fostering a rich diversity of 3D printing platforms, including fused deposition modeling, stereolithography, digital light processing, and direct-ink-writing. These technologies have empowered the creation of objects with complex geometries, offering a transformative approach to manufacturing. More recently, the advent of 4D printing has brought together the progress in 3D printing and cutting-edge materials. This innovation allows to produce objects that possess the remarkable ability to dynamically evolve, adapt, or self-assemble over time, in response to varying stimuli like alterations in temperature, humidity, or environmental factors. This dynamic dimension adds a profound layer of versatility to 3D printing, unlocking applications in biomaterials and beyond. In this special issue, we present a collection of reviews, perspective, and research articles, that highlight the latest advancements in 3D and 4D printing. This special issue unfolds in two distinctive parts: the initial section delves into the latest advancements in 3D printing, while the subsequent part sheds light on the progress in 4D printing techniques dedicated to the creation of advanced materials. Through these articles, readers will traverse a diverse landscape of innovations, ranging from the design of novel photoinitiator systems to the intricate fabrication of functional materials with applications spanning across fields like biomaterials, soft robotics, cloaking technologies, and illusion devices. This compilation serves as a comprehensive exploration of the ever-evolving landscape of 3D and 4D printing, offering insights into their profound impact on materials science and beyond. While remarkable progress has been made in 3D printing,[1] significant challenges persist, such as expanding the range of printable materials to include composites and biomaterials, while simultaneously improving production speed and feature resolution without inflating costs. Addressing these challenges requires innovative approaches, including the implementation of modern polymerization techniques, such as controlled/living radical polymerization and development of efficient photoinitiator systems to accelerate printing processes.[2] In a review article, Boyer and coworkers provide an overview of the emergence of photocontrolled reversible–deactivation radical polymerization techniques in the field of 3D printing.[2] This approach imparts a “living character” to materials, granting them access to advanced properties. These properties encompass the capability for real-time adjustments of surface and bulk properties, self-healing attributes, and precise control over nanostructuration and mechanical properties. In the pursuit of enhancing the efficiency photoinitiator system, in article 2300571, Blasco and coworkers delved into this endeavor, exploring the utilization of 4 donor–acceptor–donor photoinitiators featuring 4H-pyranylidene and 4-methylcyclohexan-1-one units as donor and acceptor groups, specifically tailored for two-photon laser printing. Furthermore, in the pursuit of optimizing 3D printing processes for novel resins, traditional reliance on empirical methods has proven to be a meticulous and time-consuming procedure. To address this challenge, in article 2300052, Page and colleagues from the University of Texas (Austin) introduced an innovative method based on the modification of Jacob's equation, which is conventionally used in stereolithographic 3D printing. To validate this innovative model, the research team conducted experiments using a green-light liquid-crystal-display 3D printing system. Additionally, the improvement of the