An elastomer is a three-dimensional network with a cross-linked polymer chain that undergoes large deformation with a small external force and returns to its original state when the external force is removed. Because of this hyperelasticity, elastomers are regarded as one of the best candidates for the matrix material of soft robots. However, the comprehensive performance required of matrix materials is a special challenge because improvement of some matrix properties often causes the deterioration of others. For example, an improvement in toughness can be realized by adding a large amount of filler to an elastomer, but to the impairment of optical transparency. Therefore, to produce an elastomer exhibiting optimum properties suitable for the desired purpose, very elaborate, complicated materials are often devised. Here, we have succeeded in creating an optically transparent, easily fabricated elastomer with good extensibility and high toughness by using a polyrotaxane (PR) composed of cyclic molecules and a linear polymer as a cross-linking agent. In general, elastomers having conventional cross-linked structures are susceptible to breakage as a result of loss of extensibility at high cross-linking density. We found that the toughness of the transparent elastomer prepared using the PR cross-linking agent is enhanced along with its Young's modulus as cross-linking density is increased.

中文翻译：

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使用聚轮烷交联剂作为分子滑轮的光学透明、高韧性弹性体。

弹性体是一种具有交联聚合物链的三维网络，在很小的外力作用下会发生较大的形变，当外力去除时又恢复到原来的状态。由于这种超弹性，弹性体被认为是软机器人基体材料的最佳候选材料之一。然而，基体材料所需的综合性能是一个特殊的挑战，因为某些基体性能的改善往往会导致其他性能的恶化。例如，通过在弹性体中添加大量填料可以实现韧性的改善，但会损害光学透明度。因此，为了生产具有适合所需目的的最佳性能的弹性体，通常设计出非常精细、复杂的材料。在这里，我们通过使用由环状分子和线性聚合物组成的聚轮烷（PR）作为交联剂，成功地创造了一种光学透明、易于制造的弹性体，具有良好的延伸性和高韧性。一般而言，具有常规交联结构的弹性体由于在高交联密度下失去延伸性而易于断裂。我们发现，随着交联密度的增加，使用PR交联剂制备的透明弹性体的韧性和杨氏模量都得到增强。