The passive systems for anti-ice protection investigated in MAI-TAI are going to be based on a polymer matrix (polyurethane PU) and mostly on the combination of two concepts, concretely low-E polymers and nanoadditives with the aim to obtain superhydrophobicity together with a minimum sliding angle. These solutions combine the principal advantages of the two strategies and allows to modify chemically the polymeric matrix and at the same time to control the nano- and micro-rugosity of applied coating and hence to reduce contact angle, increase hydrophobicity and to provide ice-phobicity to the treated surface.- Milestones achieved -
Regarding anti-icing coatings, among the results of the project is a coating generated by the electrospinning technique based on the Slippery Liquid Infused Porous Surface strategy, which reduces adherence to ice by up to 91% compared to aeronautical surfaces such as aluminum alloys and has a 1000 times higher corrosion resistance.
Comparing the coating with a material considered to have low adherence to ice, PTFE, the solution reached in MAI-TAI obtains 4 times better results.
Superhydrophobic coatings have also been achieved by combining nanoparticles with low surface energy polymers that are easily applicable and compatible with the different surfaces used, as well as with the active solutions developed. The superhydrophobic property is very useful for surfaces in combination with active systems and in areas not protected against ice where melted ice can reach in previous stages.
For the development of new technologies it is essential to know the characteristics of our system. Therefore, is essential to evaluate the ice protection systems by means of laboratory tests in similar conditions to the real ones that allow to demonstrate the mitigation of the formation of ice, the favoring of its detachment or the reduction of the necessary energy for these purposes. The greatest difficulty lies in generating supercooled water droplets with a MVD in the order of microns. In addition, the conditions of speed and LWC must also be reproduced.- Milestones achieved -
Regarding the characterization of the proposed solutions, all decisions are being made based on tests carried out in an ice tunnel with conditions similar to those of icing in-cloud.
The characterization of materials in situations similar to the real one is essential, since the behavior and consumption are radically modified by the effect of variables such as the micrometric drop size, the impact speed of the drops on the surface or the influence of forced convection on the heating of materials.
The tests are monitored using different techniques that allow obtaining a lot of information on the behavior of the systems to be studied, such as images from different angles or thermographic characterization of the surfaces in vivo.
A methodology has been developed that allows evaluating passive systems in comparison with other passive ones, but also their effectiveness in combination with an active system, forming part of a hybrid. In this way, the development of the systems can be optimized separately and later combine the most effective ones.
Within the framework of the project, studies are also being carried out on the behavior of the materials in different areas of the aircraft affected by ice so that, knowing the problem and the conditions, it is possible to discern which solution is most suitable for each area, since there are no a universal solution that works well in all circumstances.
Thanks to the MAI-TAI project, two systems for evaluating the adhesion of ice by rotation are being launched in Spain, similar to the one existing at the Anti-Icing Materials International Laboratory: AMIL, a reference used by many research groups and manufacturers in the field of the icing. One of them is already available and working, generating results for the project and for clients who request it, and the other will be available shortly, being able to test adherence to active systems in this second one as well.