4D Printing of Hydrogels: A Review

Future of additive manufacturing: Overview of 4D and 3D printed smart and advanced materials and their applications

Reversible energy absorbing meta-sandwiches by FDM 4D printing

Most of the biomedical materials printed using 3D bioprinting are static and are unable to alter/transform with dynamic changes in the internal environment of the body. The emergence of four-dimensional (4D) printing addresses this problem. By preprogramming dynamic polymer materials and their nanocomposites, 4D printing is able to produce the desired shapes or transform functions under specific conditions or stimuli to better adapt to the surrounding environment. In this review, the current and potential applications of 4D-printed materials are introduced in different aspects of the biomedical field, e.g., tissue engineering, drug delivery, and sensors. In addition, the existing limitations and possible solutions are discussed. Finally, the current limitations of 4D-printed materials along with their future perspective are presented to provide a basis for future research.

4D-Printed Dynamic Materials in Biomedical Applications: Chemistry, Challenges, and Their Future Perspectives in the Clinical Sector.

4D printing of shape memory polylactic acid (PLA)

Revitalizing interface in protonic ceramic cells by acid etch

Although 3D printing was invented in 1984, it was not until recent years that it captured the imagination of everyone from industry experts to at-home hobbyists. Three-dimensional printing, also known as additive manufacturing or rapid prototyping, constructs an object by accumulating materials layer by layer. In recent years, 3D printing technology has been dramatically developed with respect to materials, printer, and process, which laid a foundation for 4D printing. Four-dimensional printing is the targeted evolution of the 3D-printed structure, concerning shape, property, and functionality. The object is produced by 3D printing firstly. Then, the object can self-deform, self-assemble, self-disassemble, self-repair, and change property or functionality over time when the external stimuli are imposed on it. This review mainly introduces the stimulus, types of shape-shifting behaviors, mechanisms of deformation, and applications of 4D printing.

Review of mechanisms and deformation behaviors in 4D printing

Cold start capability and durability of electrospun catalyst layer for proton exchange membrane fuel cell

Alternate Hydrogen Pump Method Enables Start-Up from -30°C for Graphite-Bipolar-Plate Proton Exchange Membrane Fuel Cells

Performance of stainless steel interconnects with (Mn,Co)3O4-Based coating for solid oxide electrolysis

Han Ding

Papers

Revitalizing interface in protonic ceramic cells by acid etch

Review of mechanisms and deformation behaviors in 4D printing

Cold start capability and durability of electrospun catalyst layer for proton exchange membrane fuel cell

Alternate Hydrogen Pump Method Enables Start-Up from -30°C for Graphite-Bipolar-Plate Proton Exchange Membrane Fuel Cells

Performance of stainless steel interconnects with (Mn,Co)3O4-Based coating for solid oxide electrolysis