In research published inNature Materials, a team led by scientists from the RIKEN Center for Emergent Matter Science in Japan has developed a new hydrogel that works like an artificial muscle–quickly stretching and contracting in response to changing temperature.
他们还设法使用聚合物来构建一个L形物体，该物体随着温度反复升高和降低而慢慢向前走。
水凝胶是可以在其网络中维持大量水的聚合物。因此，它们可以响应环境变化（例如电压，热和酸度）而膨胀和收缩。从这个意义上讲，它们实际上与植物细胞相似，植物细胞能够改变形状，因为它们内部的水量随着环境条件的响应而变化。
但是，大多数水凝胶的做法非常缓慢，必须吸收和排泄水以扩展或收缩体积。Riken团队开发的水凝胶的独特特性在于它的作用像是人造肌肉，该肌肉并非在各个方向上平等收缩。
相反，他们在一个维度上收缩，同时扩展另一个维度，这意味着它们可以反复改变形状而无需吸收或排泄水。
新水凝胶属性的秘诀是静电费。使用他们在今年早些时候发布的方法，该团队通过使用磁场将金属氧化物纳米片整理到材料中的单个平面中，然后使用称为光触发的原位乙烯基聚合的程序将其固定在适当的位置，从本质上讲，这实际上是使用光将物质凝结成水凝胶。
纳米片最终被困在聚合物中，在单个平面上对齐。由于静电力，板上的板在一个方向上产生静电性，但不能在另一个方向上产生静电性。
According to author Yasuhiro Ishida, “We originally designed this material to be stretchable in one direction, but we also found that at a temperature called the lower critical solution temperature, which we calculated to be 32 degrees Celsius, the polymer rapidly changed shape, stretching in length. Intriguingly, the gel did not change in volume. The substance underwent the change in shape in air and in a liquid environment, showing that it doesn’t require the uptake of water. So in other words, it will work even in a normal air environment.”
The team members were intrigued to find, additionally, that the process was very fast, taking just one second, with the rate of deformation, at about 70% per second, being higher than what has been seen in other hydrogels.
As a demonstration of how the polymer could be put to practical use, the group designed an L-shaped piece of polymer that can actually walk, in a water environment, as the legs lengthen and contract in response to changing temperature.
该小组现在计划进行进一步的研究，以创建可用于实际应用的物质。伊希达（Ishida）说：“我们现在正在计划进一步的工作以改善该物质的特性。一个想法
we have is to use a hydrogel like this to make artificial muscles that could automatically open and close radiator systems as temperatures rise and fall. This could be used, for example, to prevent a device from overheating.”
Filed Under:Materials • advanced
