Protective Suit Inspired by 'Seupaideomaen's Secret' to Be Released

[Agency for Defense Development]Earth was formed 4.5 billion years ago, and as countless life forms emerged, organisms have continuously evolved in various ways to adapt to new environments. Humanity has been making relentless efforts to study and learn from the unique ways diverse life forms exist in nature and to apply these insights to human life. 'Biomimetics' originates from the Greek words 'bios,' meaning life, and 'mimesis,' meaning imitation or mimicry. As the name suggests, the purpose of biomimetics is to solve various problems faced by humanity through the study and imitation of design elements or characteristics of living organisms found in nature.

Janine Benyus, a pioneer in biomimetics, defined biomimetics as 'innovation inspired by nature.' Biomimetic technology is utilized in many fields, including the synthesis of artificial and novel biomaterials, intelligent system design, and the design of biomimetic devices or systems. Recently, the Agency for Defense Development has been conducting research on functional surfaces mimicking the nanostructure of lotus leaves by applying this technology.

▲ How to realize superhydrophobic surfaces= The wettability of a material surface is determined by surface energy, but when the surface microstructure is controlled into a complex structure at the micro and nano levels, non-wettability is drastically increased, enabling the realization of superhydrophobic surfaces with a water contact angle of over 150°. Even surfaces treated with fluorine functional groups, which have the lowest surface energy (high liquid repellency), only achieve a maximum water contact angle of about 120°. However, when a low surface energy material is applied to a surface with a nano hierarchical structure, water droplets do not easily form and roll off easily, exhibiting superhydrophobic properties.

Most artificially created superhydrophobic surfaces have been developed inspired by natural nanostructures. Common natural materials known for superhydrophobicity include plant leaves such as lotus and rice leaves, insect wings like cicada and butterfly wings, the footpads of the gecko, and the legs of water striders, totaling over 200 types. Their surfaces have contact angles greater than 150°, resulting in strong water repellency, where water droplets easily roll off even with a slight tilt.

▲ Research on water- and oil-repellent surface treatment and enhanced protective performance of chemical, biological, radiological, and nuclear (CBRN) protective clothing mimicking lotus leaf nanospike structures= The surface of CBRN protective clothing must exhibit oil-repellent properties to repel liquid chemical agents (surface energy approximately 24.5~42.5 mN/m) with very low surface energy, as well as water-repellent properties to repel water (72.8 mN/m) and biological agents (microorganisms, viruses, etc.) that cause infections. Therefore, protective clothing incorporating micro/nano spike-based superhydrophobic and oleophobic technologies can primarily repel high-concentration liquid chemical agents, minimizing the amount of agents penetrating into the clothing in gaseous form, thereby maximizing the lifespan of the protective clothing.

Additionally, biological agents such as microbial particles or bacteria and viruses present in liquid form are repelled along with water on the surface of the protective clothing, making it difficult for bacteria to approach and thus maintaining antibacterial properties for an extended period. In particular, by structuring nanoparticles on the surface of protective clothing using fine nanostructure patterns found on cicada wings or seaweed surfaces such as green and brown algae, it is possible to develop safe protective clothing. These nanoparticles possess inherent properties that penetrate and destroy cell membranes and antibacterial actions that pierce bacterial cell walls, effectively protecting against microorganisms.

Recent studies have reported that when nanostructured surfaces are roughened as 'antifouling' materials, the bacterial cell wall destruction reaction occurs faster than the oxidative reaction-based Escherichia coli killing method, achieving 100% E. coli eradication within 15 minutes. Applying surface repellent properties mimicking nanostructures to military uniforms or protective clothing can protect soldiers from liquid chemical agents (chemical weapons such as VX, GD, HD) and biological agents (biological weapons such as pathogenic microorganisms, viruses, toxins). The Agency for Defense Development considers the surface repellent properties mimicking nanostructures as a crucial technology and is conducting research to ensure the survivability of soldiers operating in diverse and special contamination environments.

▲ Micro- and nano-structure of fabric surfaces and superhydrophobic and oleophobic surface treatment process technology= Recently, due to concerns about the human toxicity of fluorine-based resins, coatings of fluoropolymers with long perfluorocarbon chains (eight or more carbons, C8) used for CBRN agent protection have been restricted. Therefore, the Agency for Defense Development is conducting optimization process research to achieve superomniphobic surfaces on fabric surfaces using nanostructuring and eco-friendly materials (fluoropolymers with short perfluorocarbon chains (C6 or less) or non-fluorinated materials).

To implement highly liquid-repellent superhydrophobic and oleophobic surfaces on fabrics, there are two processes: one is a top-down approach where the surface is etched to create nanostructures and then coated with low surface energy materials; the other is a bottom-up approach where low surface energy nanomaterials are deposited to form nanostructures. The Agency for Defense Development has introduced a hybrid surface system process that combines the advantages of both methods.

Through this, research is currently underway to form new micro/nano structures applicable to fabric surfaces with excellent durability. This technology is expected to domestically produce a new concept of eco-friendly superhydrophobic and oleophobic fabrics in line with the global trend of strict regulations on fluoropolymers and to be applied to future CBRN protective clothing for soldiers.

This content was produced with the assistance of AI translation services.