Heat-shrinkable films commonly serve as active materials for self-folding owing to their capability to fold all hinges upon heating. For origami-based electronic devices, the self-folding of the metal layer is necessary. Nevertheless, the self-folding angle is low owing to the high bending stiffness of metal layers and the low adhesion of heat-shrinkable films. Here, we introduce a bilayer self-folding technique that effectively suppresses delamination of the shrink layer, thereby achieving a high folding force and angle. A polyolefin film mechanically fixed on the metal substrate serves to inhibit delamination, regardless of the adhesive properties of the shrink layer. This is achieved by applying adhesives within holes fabricated on the shrink layer. Conventional methods using an adhesive layer to fix the shrink layer lead to delamination at temperatures above 100°C, resulting in a decrease in self-folding angles. In contrast, our novel fixing method yields a folding angle of 161° at 140°C, with a shrinkage rate of 69%. To demonstrate the versatility of our proposed technique, we self-fold various origami structures, including Miura-ori, scissors, cranes, and tessellation with chip LEDs. The introduced method broadens the range of substrate materials suitable for self-folding and offers new possibilities for the development of origami devices. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

中文翻译：

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通过抑制收缩层分层实现高折叠力和角度的双层自折叠方法

热收缩薄膜通常用作自折叠活性材料，因为它们能够在加热时折叠所有铰链。对于基于折纸的电子器件，金属层的自折叠是必要的。然而，由于金属层的弯曲刚度高和热收缩膜的粘合力低，自折叠角度低。在这里，我们介绍了一种双层自折叠技术，可以有效抑制收缩层的分层，从而实现高折叠力和角度。无论收缩层的粘合性能如何，机械固定在金属基材上的聚烯烃薄膜都可以抑制分层。这是通过在收缩层上制作的孔内涂抹粘合剂来实现的。使用粘合剂层固定收缩层的传统方法会在100°C以上的温度下导致分层，从而导致自折叠角度减小。相比之下，我们的新型固定方法在 140°C 下可产生 161° 的折叠角度，收缩率为 69%。为了展示我们提出的技术的多功能性，我们自行折叠了各种折纸结构，包括 Miura-ori、剪刀、起重机和芯片 LED 镶嵌。所提出的方法拓宽了适合自折叠的基底材料范围，为折纸装置的开发提供了新的可能性。 © 2024 日本电气工程师协会和 Wiley periodicals LLC。