## 2 Materials and Methods
### Overall Classification of the Materials  
As the aim of this procedure is to evaluate each material's ability to assist in manual de-icing, their individual results were compiled to obtain an overall ranking. The results used for this ranking are presented in Table 4. As specified in the methodology, the icephobic behaviors were regrouped to produce one rating out of five. The icephobic rating was obtained using the average of their reduction factor as compared to the reference aluminum. The best overall coating regarding the icephobic behavior was Nusil with a rating of 5.0, followed by SurfEllent with 3.0, then Swix with 2.9, and then WearIon with 1.3. Aluminum was awarded a rating of 0.4 for comparison purposes. The ratings obtained from the MTA using the four targeted conditions were used without any further modification, with an individual maximum score of 20. Figure 13: (**A**) Commercial gloss and (**B**) military matte-painted tail blade profiles. The final results for each material were given a score out of 85. The criterion that stipulates if a material can assist in a manual de-icing is to obtain an overall result higher than that of the aluminum reference. Given this criterion, all tested materials could assist the manual de-icing since each of them received a score higher than that of aluminum, i.e., greater than 25.4. The material with the best performance was found to be Surfellent with a score of 43.0, followed by Swix with 42.9. The slight difference between the two materials is due to the poor results obtained in the CAT for Swix where the ice had significantly more adherence. The third ranked material was Nusil, even though it demonstrated increased icepphobic behavior, it reacted negatively under snow conditions. Finally, the last ranked material was Wearlon, which performed somewhat like aluminum in some conditions, for example, in the MTA high-intensity freezing rain. From these results, it is important to note that, although a material may show promising results using the CAT or PO, it is not inherent that it will behave the same way when subjected to different icing or snowing precipitation. CAT and PO are good predictors; however, other icing conditions need to be evaluated before claiming a material to be icepphobic. It is important to note that other significant factors could be integrated within the evaluation process throughout this procedure. One important factor that could be added is the evaluation of the coating's mechanical resistance, especially if the targeted application is in aerospace for aircrafts or rotorcrafts. The critical surfaces of these aircrafts are subjected to several inclement conditions such as rain and sand. It is important to recognize that ice can also undermine the integrity of a coating and significantly reduce its efficiency. Erosion that occurs during normal operation, especially to leading edges, is a serious issue that needs to be evaluated prior to large-scale implementation. Standard tests that are documented and well known to the industry could be used and given a certain weighted percentage within the procedure. On the other hand, a pass/fail criterion could be implemented depending on its criticality. A second factor that could be added to this analysis is a weighted score reflecting the ease of application. Treating already deployed rotorcrafts with a new material like a coating could be easily done if the method does not require multiple layers or pre-treatments. Finally, this procedure can be modified to better reflect the needs of the end-user by allocating more weight to a characteristic that is deemed significant for the targeted field of application. Using our classification as an example, if the icing condition deemed to be the most relevant is light-intensity freezing rain and snow is no longer considered to be significant, by increasing the weighted score of LZR to 50 and decreasing all others to 10, the final result would indicate that Nusil should be considered as the coating of choice.