NTU Singapore Scientists Create Paper-Like Material from Pollen

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2020年4月7日

Scientists at Singapore's Nanyang Technological University (NTU Singapore) have created a paper-like material derived from pollen that bends and curls in response to changing levels of environmental humidity.

由花粉制成的本文因响应外部刺激而改变其机械特性的能力可能会使其在广泛的应用中有用，包括软机器人，传感器，人造肌肉和发电机。

Combined with digital printing, pollen paper may hold promise for the fabrication of a new generation of programmable natural actuators - components in a machine that are responsible for moving and controlling a mechanism.

这些发现，发表在美利坚合众国国家科学院论文集欧洲杯线上买球本周，展示NTU新加坡团队如何使用软化的花粉颗粒制定纸张。

They demonstrated the pollen-based paper's properties by folding it into a flower that 'blooms' in the presence of water vapor. They also showed that the pollen material's physical properties can be adjusted, with a strip of pollen-based paper that is able to 'walk'.

本文的相应作者是化学与生物医学工程学院的助理教授Juha，以及NTU的Cho Nam-Joon教授和Subra Suresh教授。欧洲杯足球竞彩欧洲杯线上买球

Much progress has been made in developing bioinspired sensors and actuators based on engineered synthetic materials, but these materials come with limitations such as issues with environmental sustainability and relatively high cost. There remains a critical need to incorporate cost-effective and eco-friendly materials. Just as pine cones open and close their scales depending on the amount of moisture in the air, our NTU research team has shown that pollen paper created from naturally abundant pollen grains responds as an actuator to changes in environmental humidity."

NTU杰出大学教授Subra Suresh，也是NTU主席

NTU Professor Cho Nam-Joon, who holds the Materials Research Society of Singapore Chair in Materials Science and Engineering, said: "These findings build on the recent work by our NTU team, in which we showed how hard pollen grains can be converted into soft microgel particles that alter their properties in response to external stimuli. This process also renders pollen and the products we create from it, non-allergenic."

弯曲，翻转和移动的花粉纸

为了形成纸张，NTU团队首先通过类似于传统的肥皂制造的过程将超凹度花粉颗粒从向日葵转变为一种类似柔软的凝胶材料。该过程包括去除在碱性条件下孵育花粉几个小时之前，取下粘粒谷物表面的粘性花粉水泥。

The resulting gel-like material is then cast into a mold and left to dry, forming a paper-like material. Using scanning electron microscopy, the scientists observed that the pollen-based paper comprises alternating layers of pollen particles, with the top layer significantly rougher than the bottom layer.

The top surface of the pollen paper, which appears frosted to the naked eye, showed remnants of the sunflower pollen grains' distinct spikes, contributing to its roughness. The bottom surface, which takes on a mirror-like surface finish, was relatively smoother.

花粉颗粒层的这种结构差异意味着，在存在水蒸气的情况下，纸开始弯曲，在干燥条件下，它会不弯曲。潮湿和干燥条件的重复循环会导致纸随着时间的推移进行翻转运动。

NTU助理教授Song Juha解释说：“在水或水蒸气吸收期间，纸张中的花粉颗粒膨胀并扩展。由于花粉颗粒层的结构差异，纸张在不同部分的膨胀膨胀。欧洲杯猜球平台纸的厚度，迫使其弯曲。”

为了表明可以自定义花粉纸的水蒸气反应性，该团队调整了加工参数，主要是花粉粒的碱性孵育时间。他们加入了两个花粉纸样品，每个样品在不同的孵化时间（3小时12小时）下制备，形成一条带有可见边界的双材料花粉纸。

当双材料花粉纸暴露于潮湿的干燥周期时，两张花粉纸样本对湿度的不同反应导致纸张像毛毛虫一样“行走”，就像毛毛虫通过交替扩展和收缩其柔软的身体而移动。

科学家还通过通过花粉纸制成的花朵来表明花粉纸作为一种自我启动的软机器人的潜在应用，该花朵通过逐渐吸收水蒸气来“开花”。