The materials scientists have made a paper from the pollen of sunflower, which due to its structure may curl depending on the humidity of the environment. With this effect they made an artificial flower, which is able to open up and self-propelled biorobot. Article published in the journal Proceedings of the National Academy of Sciences.
Many organisms adapt to the surrounding conditions to perform its biological functions. For example, the opening angle pine cone depends on the relative humidity in too wet conditions bump will remain closed. This mechanism works due to the fact that proteinaceous materials, such as silk or collagen, change their molecular conformation depending on humidity. Based on this scientists create synthetic soft actuators that can change their characteristics depending on external conditions. Scientists see their applications in soft robots, artificial muscles, sensors and electric generators.
Smart actuators based on graphene or synthetic polymers of the road, it is difficult controlled and poorly utilized, and therefore cheaper materials of natural and renewable resources. And, although natural materials such as agarose and cellulose, already used, they are isolated from raw materials and processes with significant energy costs. Moreover, some actuators are constructed from natural polymers that show weak response to changes in external conditions, and usually they are not suitable for cyclic processes change the mechanical characteristics.
Jie Zhao (Zhao Ze) with their counterparts from Nanyang technological University have created a flexible paper from the pollen of sunflower, which is capable of cyclical and reversible changes in the humidity. They presented a method of converting soft microgels of pollen in a flexible and transparent flat sheets, in which the propulsion power varies by the thickness of the sheet or the conditions of production.
Pollen particles — natural purpose micro containers, which carry the genetic material of the plant. Scientists have long been studying them virtually indestructible thanks to the structure of the pollen must retain its contents under severe adverse conditions. Pollen consists of two layers: a tough sporopollenin outside and soft pulp inside. The double bond of the ether and acetylenic groups contributes to the high mechanical hardness and chemical inertness reputed.