Kanu Nand Jee, Gupta Eva, Vates Umesh Kumar, Singh Gyanendra Kumar
S. V. National Institute of Technology Surat India
Amity University Uttar Pradesh India.
RSC Adv. 2019 Nov 22;9(65):38209-38226. doi: 10.1039/c9ra07342f. eCollection 2019 Nov 19.
4D printed objects are indexed under additive manufacturing (AM) objects. The 4D printed materials are stimulus-responsive and have shape-changing features. However, the manufacturing of such objects is still a challenging task. For this, the designing space has to be explored in the initial stages, which is lagging so far. This paper encompasses two recent approaches to explore the conceptual design of 4D printed objects in detail: (a) an application-based modeling and simulation approach for phytomimetic structures and (b) a voxel-based modeling and simulation approach. The voxel-based modeling and simulation approach has the enhanced features for the rapid testing (prior to moving into design procedures) of the given distribution of such 4D printed smart materials (SMs) while checking for behaviors, particularly when these intelligent materials are exposed to a stimulus. The voxel-based modeling and simulation approach is further modified using bi-exponential expressions to encode the time-dependent behavior of the bio-inspired 4D printed materials. The shape-changing materials are inspired from biological objects, such as flowers, which are temperature-sensitive or touch-sensitive, and can be 4D printed in such a way that they are encrypted with a decentralized, anisotropic enlargement feature under a restrained alignment of cellulose fibers as in the case of composite hydrogels. Such plant-inspired architectures can change shapes when immersed in water. This paper also outlines a review of the 4D printing of (a) smart photocurable and biocompatible scaffolds with renewable plant oils, which can be a better alternative to traditional polyethylene glycol diacrylate (PEGDA) to support human bone marrow mesenchymal stem cells (hMSCs), and (b) a biomimetic dual shape-changing tube having applications in biomedical engineering as a bioimplant. The future applications would be based on these smart and intelligent materials; thus, it is important to modify the existing voxel-based modeling and simulation approach and discuss efficient printing methods to fabricate such bio-inspired materials.
4D打印物体被归类在增材制造（AM）物体之下。4D打印材料具有刺激响应性且具备形状变化特征。然而，制造此类物体仍是一项具有挑战性的任务。为此，必须在初始阶段探索设计空间，而目前这方面仍较为滞后。本文详细介绍了两种探索4D打印物体概念设计的最新方法：（a）一种用于仿植物结构的基于应用的建模与仿真方法，以及（b）一种基于体素的建模与仿真方法。基于体素的建模与仿真方法具有增强功能，可在进入设计流程之前对这类4D打印智能材料（SMs）的给定分布进行快速测试，同时检查其行为，特别是当这些智能材料受到刺激时。基于体素的建模与仿真方法通过双指数表达式进一步改进，以编码受生物启发的4D打印材料的时间相关行为。形状变化材料的灵感来源于生物物体，如对温度或触摸敏感的花朵，并且可以通过4D打印，使其在纤维素纤维受限排列下具有分散、各向异性膨胀特征，就像复合水凝胶的情况一样。这种受植物启发的结构在浸入水中时会改变形状。本文还概述了对以下4D打印的综述：（a）用可再生植物油制备的智能光固化和生物相容性支架，它可以作为传统聚乙二醇二丙烯酸酯（PEGDA）的更好替代品来支持人骨髓间充质干细胞（hMSCs）；（b）一种在生物医学工程中作为生物植入物应用的仿生双形状变化管。未来的应用将基于这些智能材料；因此，修改现有的基于体素的建模与仿真方法并讨论制造此类受生物启发材料的有效打印方法很重要。
