Hello...I left an excerpt from the article and the points that I didn't really understand about it are in bold.
1. I didn't understand about this crystal clear water. I was able to research is that there are actually some crystals in the part of the molecules of the water itself, but I don't know exactly how it is really explicit in the same subject of the article.
2. I understood that certain perchlorates have this crystallized and hygroscopic water this can be a disadvantage in the long run, but I did not understand why it is still necessary to have this crystalline water to stabilize the pores of the silicon pores.
Highly explosive nanosilicon-based composite materials - https://www.researchgate.net/public...plosive_nanosilicon-based_composite_materials
Due to packaging and long-term stability reasons only solid oxidizers incorporated into the pores of PSi have been explored. The most efficient oxidizers are perchlorates, since they have high oxygen content and are relatively stable in comparison to other oxidizers, e.g. chlorates. Therefore, we have chosen perchlorates as first choice for oxidizer. Unfortunately, most of the perchlorates contain crystal water and are hygroscopic (see Table 2). Non-hygroscopic perchlorates are KClO4 and RbClO4 but they are not solvable in common solvents. We found that perchlorates are much more efficient for explosive interaction than the analogue nitrates. We didn’t find any other oxidizer comparable with perchlorates but, because the energy yield of the reaction is very high, less efficient oxidizers can be sufficient for the possible industrial applications. On one hand, crystal water and hygroscopic nature of perchlorates are certainly disadvantages because they cause problems with long term stability of the samples. On the other hand, according to our experience it seems that at least the crystal water is necessary for stabilizing the salt inside of the pores. For instance, NH4ClO4 is not hygroscopic and contains no crystal water but after evaporation of the solvent it also creeps away of the pores. exactly how it is really explicit in the same subject of the article.