IFGW researchers who won covers in
Scientific publications also use models from 100 years ago

Darwin inspires
nanotechnology solutions


LUIZ SUGIMOTO

O Professor Douglas Soares Galvão, from the Gleb Wataghin Institute of Physics (IFGW) at Unicamp, is immersed up to the roots of his hair in so-called nanotubes, microscopic cylinders composed of carbon that, in fact, are 100 times thinner than a strand of hair. In the eyes of researchers, this material, due to its rigidity and electrical conductivity, will mainly revolutionize the area of ​​electronics in the coming years. Among many other applications, it will be able to replace silicon as the raw material for current oscillators that generate and capture electromagnetic waves in radio, television and cell phone transmissions.

Cylinders are designed on a nanometric scale

Galvão coordinates a line of research in which these cylinders are designed on a nanometric scale - one billionth of a meter - and their mechanical properties are simulated on a computer to create new devices. A work that the professor signed together with Sergio Legoas, Vitor Coluci, Scheila Braga, Pablo Coura and Sócrates Dantas was already featured on the cover of Physical Review Letters, the main physics magazine, in February 2003, and an expanded version of this article was given another cover , from Nanotechnology, now in April. Two covers for the same work reflect unusual prominence among scientific publications. "There is still no nanooscillator capable of operating at 1 gigahertz (GHz) [hertz is the unit of measurement that corresponds to one oscillation per second]. The article had the merit of demonstrating that nanooscillators can reach 50 or 70 GHz)", justifies.

However, what could researchers involved in future technology learn from Charles Darwin? Douglas Galvão will offer some more details about nanotubes on this page, but in the middle of the conversation he comes across two other works, still unpublished, that he believes will arouse special interest among lay people because they present an unusual relationship with biology. One of the articles, which Physical Review Letters has already approved and is expected to publish in the coming weeks, describes the simulation of elastic properties of "nanomoles", which have been the subject of intense research in recent years. The peculiarity of this research is that it was inspired by Darwin's description of the structure of the vine, a spring-shaped climbing plant. In the second work, the inspiration came from "mathematical cicadas", so called because they live underground and only rise to the surface to breed in prime periods (7, 11, 13 and up to 17 years), thus reducing the risk of encountering predators. .

Imitation - A problem in nanotechnology is determining how hard nanosprings are, that is, the deformation caused by a force applied to them, both vertically and laterally. If a primary objective in this area is to reduce the space occupied by a material almost impossible, these microscopic spirals deserve attention. The IFGW professor explains that there is a very strong similarity between the zinc oxide nanosprings and the structure of the gravel, which, as it grows, curls up like the spiral of a notebook. "We used a model inspired by biology to solve an important nanotechnology problem, on a scale 1 billion times smaller", compares Galvão, who carried out this work together with Alexandre da Fonseca, a former IFGW student and who is doing a post-doctorate at the Institute of Physics at USP.

The professor explains that the materials researched in nanotechnology are too large for quantum mechanical simulations, and not large enough to use common materials engineering techniques. "We are halfway between these two worlds, offering theorists the opportunity to develop new tools. Biology has been a good place to be inspired," he illustrates. The gravel model for nanosprings, which Alexandre da Fonseca quickly adapted, showed differences of just 5% between experimental biology data and what was calculated on the computer. "By imitating nature to design some materials, we ended up solving a problem of low-dimensional elastic properties", insists the Unicamp researcher.

Cryptography - The encryption key used, for example, in security systems bank and internet security, is the adoption of the first two prime numbers being multiplied, making it very difficult to reconstruct the numerical series. That's why Douglas Galvão was so intrigued when he read about "mathematical cicadas". A family of these insects remains underground for long periods, comes to the surface for just a few weeks to reproduce and returns with their offspring underground. "The interesting thing is that they only appear in prime periods. We are trying to resolve whether this problem has any meaning in biology", says the professor.

With the help of scholars of theoretical evolution - Paulo Campos, Viviane de Oliveira, Ronaldo Giro and Vinicius Isola - Galvão began computer simulations, where the results appeared naturally, identical to the behavior of cicadas. "As predatory pressure increases, the intervals in the appearance of cicadas also increase, always at prime periods. If cicada and parasite were born every year, the predator would intercept the insect every year. If the cicada appears every two years, interception occurs every year yes, no year. But if the cicada comes to the surface only in prime periods, the chance of the predator randomly intercepting it is very small. Apparently, nature discovered encryption millions of years before men", jokes the researcher from IFGW.