Abstract
Since the late 1980s, additive manufacturing (AM), commonly known as three-dimensional (3D) printing, has been gradually popularized. However, the microstructures fabricated using 3D printing is static. To overcome this challenge, four-dimensional (4D) printing which defined as fabricating a complex spontaneous structure that changes with time respond in an intended manner to external stimuli. 4D printing originates in 3D printing, but beyond 3D printing. Although 4D printing is mainly based on 3D printing and become an branch of additive manufacturing, the fabricated objects are no longer static and can be transformed into complex structures by changing the size, shape, property and functionality under external stimuli, which makes 3D printing alive. Herein, recent major progresses in 4D printing are reviewed, including AM technologies for 4D printing, stimulation method, materials and applications. In addition, the current challenges and future prospects of 4D printing were highlighted.
Highlights
In 1986, Chuck Hull proposed that three-dimensional (3D) systems applied for a technology of stereolithography (SLA), which attracted the world’s attention and to some extent represented the origin of a 3D printing technology [1]
Additive manufacturing for four-dimensional (4D) printing is mainly divided into two categories: Extrusion-based methods [5], and vat photopolymerization methods [2,6]. 3D printing has been widely used in biomedicine, polymer science, space science, and other fields by virtue of its rapid prototyping of 3D products with complex shapes [7,8,9,10,11]
Additive manufacturing technologies used for 4D printing can be classified into several categories based on the mode of materials or ink deposition: Extrusion-based methods including fusion deposition modeling (FDM), direct ink writing (DIW) and inkjet, as well as vat photopolymerization methods including stereolithography (SLA) and digital light processing (DLP)
Summary
In 1986, Chuck Hull proposed that three-dimensional (3D) systems applied for a technology of stereolithography (SLA), which attracted the world’s attention and to some extent represented the origin of a 3D printing technology [1]. 3D printing has been widely used in biomedicine, polymer science, space science, and other fields by virtue of its rapid prototyping of 3D products with complex shapes [7,8,9,10,11]. He microstructures fabricated using 3D printing is static. Additive manufacturing technologies used for 4D printing can be classified into several categories based on the mode of materials or ink deposition: Extrusion-based methods including fusion deposition modeling (FDM), direct ink writing (DIW) and inkjet, as well as vat photopolymerization methods including stereolithography (SLA) and digital light processing (DLP)
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