M. S. M. Saifullah and Hemant Raut of A*STAR’s Institute of Materials Research and Engineering in Singapore and their co-workers have developed a coating that matches the optical properties of the best conventional anti-reflective coatings (ARCs), while being more robust and easier to produce1.
Minuscule bumps that mimic the surface of a moth’s eye maximize the amount of light transmitted through a glass sheet.
ARCs are used in a variety of applications to reduce glare and increase the proportion of light transmitted through the glass or plastic beneath — potentially boosting the output of a solar module, for example.
Roughly 8% of light is reflected as it travels from air into glass, due to the difference in the refractive index between the materials. ARCs have refractive indices that gradually change from lower to higher values, offering a smooth transition for light that minimizes reflection. The moth’s eye achieves this with a layer of tiny bumps of 250 nanometers in height, but previous polymer films that mimic this pattern lacked sufficient durability for outdoor applications.
The coating developed by Saifullah, Raut and their team is based on polyhedral oligomeric silsesquioxane (POSS) — a molecular cage built from silicon and oxygen atoms. The team combined a modified form of POSS with three different molecules that can form strong links between them, and then spun the mixture onto glass to ensure an even distribution.
Using a process called nanoimprint lithography, the scientists pressed a non-stick nickel mold onto the mixture and heated it to 130 ºC, triggering a chemical reaction that cross-linked the reagents to form a polymer film. They repeated the process to create a second film on the other side of the glass.
After testing different proportions of the ingredients, the researchers produced coated glass that transmitted 98.2% of the light shone on it, matching the highest values reported for such structures. The film improved the transmittance of light falling at a wide range of angles by gradually bending incoming light rays toward the glass.
The coating showed no degradation after 100 hours in water at 85 ºC and could withstand sulfuric acid as well as a fog of salty water. It was also more scratch-resistant than conventional polymer-based ARCs. “These properties are highly desirable in a robust ARC that is targeted for outdoor commercial applications,” says Saifullah.
“The biggest challenge is the scalability of the POSS-based ARCs for use on large-area glass substrates,” he adds. “Roll-to-roll nanoimprint lithography is the way to do it. However, factors such as throughput have to be considered before commercialization can be realized.”The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering
Move over, Superman! NIST method sees through concrete to detect early-stage corrosion
27.04.2017 | National Institute of Standards and Technology (NIST)
Control of molecular motion by metal-plated 3-D printed plastic pieces
27.04.2017 | Ecole Polytechnique Fédérale de Lausanne
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences