## 1 Introduction
[28] investigated the sputtering and micro-explosion characteristics induced by water/diesel emulsion fuel droplets impacting heated surfaces under different water contents (from 5 vol.% to 20 vol.% with an interval of 2.5 vol.%) and surface temperatures. They found that when the surface temperature is below the LFP temperature, various types of bubbles will be generated based on specific temperature values, while no bubbles can be observed for pure diesel droplets. For multi-component droplets of mixed organic liquid fuels, [PERSON] et al. [29; 30] experimentally explored the impact dynamics of gasoline and n-heptane/n-decane binary droplets on a heated wall. They discovered that the impact regime of the binary droplet is similar to that of a pure droplet, with the exception of some differences in nucleate boiling caused by the distillation characteristics of specific components. To investigate the impact dynamics of water/alcohol droplets on the heated plate, numerous studies have been conducted, exploring the effects of different types and contents of alcohol additives on the impact behavior of binary droplets, and [PERSON] et al. [9; 23] provide a detailed overview of such experiments. For low-content alcohol additives, [PERSON] et al. [8; 9; 31] conducted experimental studies and discovered that trace amounts (<8 vol.%) of alcohol additives can effectively promote the atomization and fragmentation of water droplets, raising the dynamic LFP temperature compared to that of pure water. For a wider range of alcohol additives, [PERSON] et al. [32] and [PERSON] et al. [33] explored the impact dynamics of water/ethanol binary droplets on a titanium dioxide nanotube surface and a smooth aluminum surface, respectively. Both studies revealed that the impact dynamics of binary droplets in the transition boiling state are more diverse and novel compared to those of pure droplets. Summarizing the previous work, it was found that differences in fluid physical properties can have a significant effect on impact behavior. For multi-component droplets, previous studies have focused on the effects of different mixing contents and surface temperatures in the same type of mixture. But there are few comparative studies of different types of mixtures, leading to a limited understanding of the influence of varying liquid properties on impact behaviors. In order to further investigate the effect of the interaction of different liquid physical properties on the behavior of droplet impact, a comparative study for a specific system is required. Further research and analysis are imperative to explore the boiling behavior, atomization characteristics, and bubble dynamics of multi-component droplet impact during the transition boiling stage. This study is designed to examine how the physical properties of liquids influence the behavior of binary droplet impacts on a smooth heated aluminum-alloy surface using a high-speed imaging system. Two sets of mixed solutions with comparable boiling point differences are used as working fluids. The mixtures consist of ethanol as the low-boiling-point constituent and propanol or water as the high-boiling-point counterpart, respectively. In the Results and Discussion section, first, the impact morphology as well as the impact regime map and residence times of the two binary droplets are discussed and compared. Second, the satellite droplet production and corresponding bubble dynamics for the two binary droplets in the case of nucleate boiling at the same wall temperature (\(T_{\text{s}}=120\)\({}^{\circ}\)C) are analyzed. Finally, a novel large bubble shrinkage phenomenon of ethanol/water binary droplets is observed at \(T_{\text{s}}=120\)\({}^{\circ}\)C and an ethanol content of 25%. A brief mechanistic explanation for this observation is provided.