4D打印技术:工艺、材料及应用

4D Printing:Technologies,Materials and Applications

自1980年以来,3D打印就掀起了一片研究热潮,其凭借高使用效率、出色的表面分辨率和一步生产方面的高效率优势,被广泛应用于生物医学、电子学、自愈技术、工程应用以及仿生学领域。但3D打印技术存在难以打印复杂的结构及抑制应变控制的尺寸变化和各向异性行为的技术难题。为了克服其打印尺寸复杂性和不灵活性,人们引入了4D打印的概念。4D打印是基于智能材料、3D打印机和设计的跨学科研究,与3D打印产出的静态结构相比,4D打印产出的是一个动态结构。4D打印允许3D打印的结构响应外部刺激(例如温度、光线、水等),并随时间改变其形状或功能,从而使打印的产品不再局限于固定的形态,而是呈现多样化。自2013年首次概念化以来,4D打印就引起了研究者极大的兴趣。第四维度赋予了设计生命力,它使用刺激来驱动智能材料形状记忆效应的转变。智能材料是对环境敏感的材料,包括聚合物、合金、水凝胶、陶瓷和复合材料等,它们在热预应变、水吸收、电磁辐射活化、磁场、电流和电压、溶剂和pH值等外部环境刺激下,随时间发生自我变形、自我组装、自我分解、自我修复并更改属性或功能,呈现出变化多样的形态特征。4D打印通过模仿自然过程(花朵盛开、植物的变化和向日葵运动等)、探究材料的近似特征,在药物输送、可穿戴电子设备、时装、自动折纸结构、传感器和其他工程应用中被广泛尝试,并取得了惊人的成果。本文聚焦于4D打印中使用的材料系统和4D打印的具体应用,简要概述了4D打印的历史、定义、原理和基本要素之后,详细介绍了4D打印材料的系统分类,阐述了4D打印技术在生物仿生、生物医疗、折纸结构等相关应用领域的发展与挑战。最后,介绍了4D打印的趋势以及新领域的发展前景,为进一步的研究提供参考。

Since the 1980s,the idea of 3D printing has set off a research upsurge.Due to its advantages of material efficiency,excellent surface resolution and high efficiency in one-step production,3D printing has been widely used in biomedical,electronics,self-healing technology,engineering applications and bionics fields.However,3D printing technology also has some shortages,it cannot control the addition technology to produce complex structure or suppress the size change and anisotropy behavior of strain control.In order to overcome the complexity and inflexibility of printing size,people introduced the concept of 4D printing.4D printing is an interdisciplinary research based on intelligent materials,3D printers and design.Compared with the static structure produced by 3D printing,4D printing contains a dynamic structure which means 4D allows 3D printed structures to respond to external stimuli(such as temperature,light,water,etc.)and change their shape or function over time,so that the printed product is no longer limited to a fixed shape,but presents a variety of changes.4D printing attracts a lot of interest since it was first conceptualized in 2013.The fourth dimension gives vitality to design,which uses stimuli to drive the transformation of smart materials by shape memory effects.Intelligent materials are sensitive to the environment which including polymers,alloys,hydrogel,ceramics,composite materials and so on.Through the environment stimuli like thermal pre-strain,water absorption,electromagnetic radiation,activation,magnetic field,current,voltage,the solvent and pH,smart materials will self-assembly produce a deformation,decomposition,repair even change the properties or functions,showing a variety of morphological characteristics.4D printing has been widely tried in drug delivery,wearable electronics,fashion,automatic origami structures,sensors and other engineering applications by mimicking natural processes(flowers bloom,plant changes and sunflower movements)and exploring similar characteristics of materials.This review focuses on the system and specific application of 4D printing materials and list a brief overview of the 4D printing about its history,definition,principle and basic composition.We look back the latest development of 4D printing materials and state both the development and challenges of related application fields like the biological bionic,biological,medical,the progress of the application of paper folding structure,etc.Finally,we introduce the trend of 4D printing and the development prospect of the new field to provide reference for further research.