1020年6月10日
Soft robots and biomedical implants that reconfigure themselves upon demand are closer to reality with a new way to print shapeshifting materials.
Rafael Verduzco and graduate student Morgan Barnes of Rice's Brown School of Engineering developed a method to print objects that can be manipulated to take on alternate forms when exposed to changes in temperature, electric current or stress.
研究人员认为这是反应性的4D打印。他们的作品出现在《美国化学学会杂志》上ACS应用材料和界面欧洲杯足球竞彩.
他们首先报道了他们在2018年在模具中制作变形结构的能力。但是，使用相同的化学反应来实现3D打印有限的结构，以使坐在同一平面上的形状。这意味着不能将没有凸起或其他复杂曲率编程为替代形状。
Verduzco说，克服将印刷过程解散的局限性是迈向更有用的材料的重要一步。欧洲杯足球竞彩
"These materials, once fabricated, will change shape autonomously,"韦尔杜兹科说。"We needed a method to control and define this shape change. Our simple idea was to use multiple reactions in sequence to print the material and then dictate how it would change shape. Rather than trying to do this all in one step, our approach gives more flexibility in controlling the initial and final shapes and also allows us to print complex structures."
The lab's challenge was to create a liquid crystal polymer "ink" that incorporates mutually exclusive sets of chemical links between molecules. One establishes the original printed shape, and the other can be set by physically manipulating the printed-and-dried material. Curing the alternate form under ultraviolet light locks in those links.
一旦设置了两个编程表格，例如，当材料加热或冷却时，材料就可以来回变形。
The researchers had to find a polymer mix that could be printed in a catalyst bath and still hold its original programmed shape.
“我们必须优化很多参数 - 从使用的溶剂和催化剂到肿胀程度和墨水配方 - 使墨水能够快速固化以迅速凝固以打印而不抑制所需的最终形状致动，”巴恩斯说。
该过程的剩余限制是能够打印不支持的结构，例如列。她说，这样做需要一种溶液，该溶液在印刷过程中足以支撑自己。获得该能力将使研究人员能够打印出更复杂的形状组合。
"Future work will further optimize the printing formula and use scaffold-assisted printing techniques to create actuators that transition between two different complex shapes,"巴恩斯说。"This opens the door to printing soft robotics that could swim like a jellyfish, jump like a cricket or transport liquids like the heart."
该论文的合着者是稻草研究生Seyed Sajadi；Shaan Parekh，德克萨斯州Sugar Land的John Foster Dulles高中的学生；水稻研究科学家穆罕默德·拉赫曼（Muhammad Rahman）；赖斯材料科学和纳米工程系主席Pulickel Ajayan，Benjamin M.和Mary Gree欧洲杯足球竞彩nwo欧洲杯线上买球od Anderson工程学教授和化学教授。
Verduzco是化学和生物分子工程以及材料科学和纳米工程的副教授。欧洲杯足球竞彩欧洲杯线上买球
韦尔奇化学研究基金会和陆军研究办公室化学科学部支持了这项研究。欧洲杯线上买球
来源：https://www.rice.edu/