3D printed surface inspired by nature

It is reported that in order to survive in extreme environments, many animals and plants have developed outstanding abilities that we can only know from the superheroes in movies.

This picture schematically shows a pattern that mimics the miniature Christmas trees, which produce the color of the famous blue Murphy butterfly. Source: RUB

In order to survive in extreme environments, many animals and plants have developed outstanding abilities that we can only know from the superheroes in movies. In most cases, their capabilities are based on the extraordinary characteristics of their surfaces. Imitating these characteristics provides great potential for developing new products and solving technical problems in the engineering field. Bochum and Kiel's research team successfully used a high-precision 3D printing technology called two-photon polymerization (2PP) to simulate the structural color of the famous blue Murphy butterfly. The researchers presented their latest findings in a paper published in the Journal of Optical Microsystems on September 2, 2022.

M. The morphology of didius surface structure and the optical properties of its blue wing surface.

The research in the field of biological simulation is carried out by the researchers of Applied Laser Technologies at Ruhr University ä t Bochum (RUB) who apply laser technology, led by Professor Andreas Ostendorf and Professor Cemal Esen, and the researchers of Kiel University (CAU) Functional Morphology and Biomechanics Group are led by Professor Stanislav Gorb.

3D printing of biological inspired Christmas tree

2PP is a laser based printing technology that can process all three-dimensional photosensitive resins. Different from traditional printing technology, it can use virtual computer models to create complex and real 3D structures without supporting structures. In addition, 2PP can achieve high resolution because a single structural feature can measure dimensions below 100 nm. This figure is about one thousandth of the thickness of human hair.

Interference aided 2PP simulation M Didius lamellar ridge.

2PP's 3D printing capabilities enable researchers to generate hierarchies at both micro and nano scales. In this way, they were able to mimic the structural colors of blue metabutterflies, including their extraordinary optical properties. The color of butterflies is formed by the small Christmas tree like structure on the surface of their upper wings. In addition, the complex physical phenomena between the light and the Christmas tree enable people to observe the blue color which is almost insensitive to the angle. Gordon Zyla, a RUB researcher, said: "This is very surprising, because the structural color usually looks like a rainbow when it is generated by similar physical phenomena (such as refraction)."

Color of bionic structure for anti-counterfeiting applications

In their current work published on the Journal of Optical Microsystems, researchers have successfully redesigned their butterfly inspired structure based on previous publications. The redesign allows them to see the blue color that is not affected by the angle evenly or only from a specific direction. To this end, they first analyzed the optical characteristics and morphology of the wing surface of the Morpho didius butterfly at the University of California. Based on their findings, they concluded that they could control the direction of angle insensitive color appearance by changing the geometric shape of their hierarchical structure only on a micro scale, while still imitating the structure of butterflies on a nano scale.

The blue structure color produced by the bionic 2PP structure and its optical properties.

For example, the novel design proposed by the author is suitable for manufacturing highly complex anti-counterfeiting features. In general, their research shows the great potential of 2PP technology in bionics. In this case, the author believes that 2PP can be combined with new photosensitive materials to simulate various functional structures in nature. Therefore, other super abilities found in organisms can also be used for different engineering applications.

Source:Two-photon polymerization as a potential manufacturing tool for biomimetic engineering of complex structures found in nature, Journal of Optical Microsystems (2022). DOI:

10.1117/1.JOM.2.3.031203