College of Chemistry and Environmental Engineering , Shenzhen University , Shenzhen 518060 , P. R. China.
Department of Chemistry , The Chinese University of Hong Kong , Shatin, N.T. , Hong Kong SAR , P. R. China.
ACS Appl Mater Interfaces. 2018 Mar 14;10(10):9077-9084. doi: 10.1021/acsami.8b01610. Epub 2018 Mar 2.
Stimuli-responsive hydrogels that undergo programmable shape deformation are of great importance for a wide variety of applications spanning from soft robotics and biomedical devices to tissue engineering and drug delivery. To guide shape morphing, anisotropic elements need to be encoded into the hydrogels during fabrication, which are extremely difficult to alter afterward. This study reports a simple and reliable mechanochemical regulation strategy to postengineer the hydrogels by encoding structures of high stiffness locally into prestretched tough hydrogels through ion transfer printing with a paper-cut. During printing, trivalent ions (Fe) were patterned and diffused into the prestretched tough gels, which dramatically increased the local stiffness by forming the second trivalent ionically cross-linked network. By removing the applied stretching force, the stiff anisotropy-encoded prestretched tough hydrogels underwent programmable shape morphing into complex three-dimensional origami structures due to the stiffness mismatch.
刺激响应水凝胶能够进行可编程形状变形，对于从软机器人和生物医学设备到组织工程和药物输送等各种应用都非常重要。为了指导形状变形，需要在制造过程中将各向异性元素编码到水凝胶中，而这在之后是极其难以改变的。本研究报告了一种简单可靠的机械化学调控策略，通过使用剪纸的离子转移印刷，将局部高刚度结构编码到预拉伸坚韧水凝胶中，从而对水凝胶进行后工程设计。在印刷过程中，三价离子（Fe）被图案化并扩散到预拉伸坚韧凝胶中，通过形成第二个三价离子交联网络，显著提高了局部刚度。通过去除所施加的拉伸力，由于刚度失配，硬各向异性编码的预拉伸坚韧水凝胶能够可编程地变形为复杂的三维折纸结构。
