Researchers Develop New Method to Tailor the Properties of Stress-Indicating Molecules

Scientists at the University of Fribourg’s Adolphe Merkle Institute (AMI) and北海道大学在日本，已经创建了一种技术来修改可以掺入聚合物并用光学信号的机械载荷中的压力指示分子的特性。

在他们的研究生物启发材料的国家能力中心进行的研究中，AMI聚合物化学和材料主席Christoph Weder教授及其小组一直在研究将其颜色或荧光特性改变机械特性的聚合物欧洲杯足球竞彩加载。

实现此操作的现有方法是基于独特设计的传感器分子，这些传感器分子由弱化学键组成，这些键在施加的机械力超出特定阈值之外时会破裂。这种效果会导致颜色变化或其他预定义的响应。但是，这种方法的主要缺点是，当暴露于热量或光线时，弱键也会破裂。由于缺乏特异性，将压力指示聚合物的实际实用性最小化。此外，它通常使效果不可逆转。

In order to tackle this issue, Weder and Dr Yoshimitsu Sagara—a Japanese researcher who worked for two years in Weder’s group at AMI before joining Hokkaido University as an Assistant Professor—developed a new kind of sensor molecule that can only be stimulated by mechanical force.

In contrast to previous force-transducing molecules, there is no breaking of chemical bond. Rather, the new sensor molecules have two parts that are mechanically interconnected. This interconnection inhibits the separation of the two parts, while still enabling them to be attracted together or repelled away from each other. Such molecular attraction and repulsion cause the molecule’s fluorescence to switch from off to on.

In a new release in the open-access journalACS Central Science, Weder, Sagara, and their co-workers state that this new idea is versatile and robust.

The design approach allows one to tailor the properties of such sensor molecules, as their behavior is quite predictable。

Christoph Weder教授，AMI聚合物化学和材料主席欧洲杯足球竞彩

We chose to demonstrate this by tackling materials that display white fluorescence when stretched。通常难以实现机械响应白色荧光。它需要三个具有预定义发射颜色的传感器分子的组合：蓝色，绿色和红色（或橙色）。此外，传感器分子还需要表现出对机械应力的相似响应。

北海道大学助理教授Yoshimitsu Sagara博士

As proposed, polymers that consist of the new motifs do not fluoresce when there is no mechanical force, but they become brightly fluorescent—red, green, or blue, when only one kind of sensor molecule was used, white when they were combined—when extended. As there is no breaking of chemical bonds, the process is also completely reversible.

Therefore, when the new sensor molecules were integrated into an elastic polymer and when it was extended, the fluorescence was turned on, and when the force was removed and the material contracted, the fluorescence was turned off. Furthermore, the fluorescence intensity, or brightness, was established to relate to the extent of deformation.

Promising applications for these materials are integrated monitors that transmit visual warning signs before a part stops working, or that allow engineers to record stresses in parts under load and help them design these better. In addition, the sensor molecules hold potential for basic, molecular-level studies of stress-transfer mechanisms in synthetic materials as well as in biological systems.

现在，瑞士日本人团体正在携手，使设计更简单，以扩展该概念，以包括改变其颜色而不是荧光的材料。欧洲杯足球竞彩可以在没有任何辅助方法的情况下检查此类图案的响应，因此对于实际应用而言更有价值。

该研究由日本科学技术局和瑞士国家能力研究生物启发的材料资助。欧洲杯足球竞彩欧洲杯线上买球

A video presentation created by the research team explaining the unique property of the polymer. Copyright Hokkaido University.