摘要
Shape memory materials possess programmable complex and large deformations towards external stimuli,which are particularly essential for their potential applications.For the transformation of planar two-dimensional(2D)structures into complex 3D structures,the design of asymmetric or bilayer thin sheets is usually required.In this paper,we propose a facile strategy to achieve these complex 3D structures that can be transformed to various pre-determined shapes sequentially by laser-triggered site-specific deformations.The response of shape memory polycaprolactone(PCL)to laser is realized by physically dopingW18O49 nanowires into the cross-linked PCL diacrylate matrix.When irradiated by 98 mW cm^(−2)laser,the pre-stretched PCL/W_(18)O_(49)film shows an out-of-plane bending deformation due to the temperature gradient and single-domain orientation on the thickness between the upper layer and lower layer.The bending rates and amplitudes of the film can be tailored by adjusting the parameters of irradiation time,the film thickness as well as the pre-stretch strain.Remarkably,the pre-stretched film can automatically bend in more intricate complex deformations by integration with kirigami cuts in planar.Finally,we demonstrate that by activating the dynamic transesterification reaction within the same film,it can also achieve the 2D-to-3D transformations.With these decent features,this kind of novel PCL//W_(18)O_(49)film shows great potential in the field of biomedical devices or soft robotics.
形状记忆材料在受到外部刺激时具备可编程的复杂形状和大变形,该特性对其潜在应用至关重要.通常情况下将平面二维结构转化为复杂三维结构需要设计非对称的或双层薄膜结构.在本工作中,我们提出了一个简单的策略以实现二维到三维结构的转变,即可以通过激光刺激预拉伸复合薄膜的特定点进而变形成各种预先确定的形状序列.具体的,将吸光性W18O49纳米线物理掺杂到丙烯酸封端的聚己内酯交联网络中,当用98 mW cm^(−2)的激光刺激复合薄膜时,温度梯度和单层薄膜在厚度维度上的单畴取向导致形状记忆聚己内酯/W_(18)O_(49)纳米线复合薄膜的面外弯曲变形.紧接着,通过调控激光辐照时间、薄膜厚度和预拉伸应变,可以实现复合薄膜的不同弯曲变形速率和弯曲幅度.此外,通过将预拉伸的平面二维状聚合物薄膜与剪纸技术相结合,复合薄膜在受激后可以朝着更为复杂的三维形状发生变化.通过激活同一薄膜内的动态酯交换反应也可以实现聚己内酯基复合薄膜的二维到三维形状转化.因此这种新型薄膜在生物医学器件或软机器人领域具有巨大的应用潜力.
作者
Guangming Tian
Guangming Zhu
Shuogui Xu
Ming Li
Renjie Tian
田光明;朱光明;许硕贵;李铭;田仁杰(Department of Applied Chemistry,School of Science,Northwestern Polytechnical University,Xi’an 710072,China;Emergency Medicine Department&Trauma Emergency Center,Changhai Hospital,Second Military Medical University,Shanghai 200433,China;Department of Applied Physics,School of Science,Northwestern Polytechnical University,Xi’an 710072,China)
