Sugar-coating technology makes airplanes invisible.

Scientists have sought to develop an aircraft coating composed of millions of tiny, hollow carbon spheres tightly packed into a single layer of carbonized sugar, which could make the aircraft invisible to radar.

A hollow carbon sphere as seen through a scanning electron microscope. Photo: D. Bychanok

According to Science Daily, these spheres will absorb all radiation in the Ka region (frequency 26.5 – 37 GHz or wavelength 7.5 – 10 mm), a frequency range commonly used by the military for radar. Besides aircraft and military equipment, anti-reflective coatings can also be used on many other surfaces, including computers and phone screens.

Based on experimental results and models, scientists found that using hollow carbon spheres with a diameter larger than the spherical structure in a moth's eye and an optimal thickness, arranged in a hexagonal pattern, can achieve near-perfect microwave absorption. In nature, thanks to these special eyes, moths can absorb light to see better in the dark and avoid predatory bats.

To create the coating, scientists from the Institute of Nuclear Problems Research at Belarusian National University coated biopolymer plastic particles with sucrose (table sugar), a type of sugar that is easily extracted from natural sources.

These particles are then burned using a special process called pyrolysis, which transforms the plastic inside into gas that escapes, while simultaneously burning the sugar into carbon. The result is hollow carbon spheres. These spheres are then further pyrolyzed at 900 degrees Celsius in a nitrogen atmosphere to create a glass-like material.

Using a coating fabricated in this way will help absorb about 95% of 30GHz radiation, according to Dzmitry Bychanok, the lead author of the study. The research team's next plan is to develop the material from two-dimensional to three-dimensional structures.

According to VnExpress