## 2 Materials and Methods
### Experimental Procedures  
The experiments were conducted using the setup presented in Figure 1. To vary the droplet size (\(R_{\mathrm{d}}\)) from 0.2 to 1.0 mm, detachable nozzles were employed: G17, G21, G25, G30. Droplets of the compositions under study were fed with a SinoMDT SN-50F6 syringe pump (infusion accuracy within 2%, 0.1 mL/h step of infusion rate adjustment, max. flow rate 1500 mL/h). A 50-mL syringe was fit in the pump. Such a pump provided a constant flow rate of liquid of approx. 100 mL/h. A spherical particle was held by a nozzle connected to the vacuum pump. A positioning mechanism controlled the particle height and centricity relative to the droplet. An allowable deviation of centricity in the experiments did not exceed 5% from the initial droplet radius. To adjust the collision centricity, the second high-speed video camera was used. Before each experiment, the particle and substrate surfaces were thoroughly cleaned with isopropyl alcohol to remove traces of liquid from the previous experiment and wiped with a hint-free cloth. In the study of droplet-substrate collisions, the substrate was placed on a lifting table. A Fastcam Mini UX100 high-speed video camera with a Sigma 105 mm f/2.8 EX DG OS HSM Macro Nikon F lens was used to record the droplet-particle collisions. The video camera settings during the experiments were as follows: frame rate--5000 fps, resolution--1280 \(\times\) 1024 pixels, inter-frame delay of 1/25,000. The key parameters of droplet-particle interaction were recorded (Figure 2): droplet radius (\(R_{\mathrm{d}}\)); particle radius (\(R_{\mathrm{p}}\)); droplet velocity (\(U_{\mathrm{d}}\)); distance between the centers of mass of the particle and droplet (\(b\)). The systematic measurement error of droplet sizes, velocities and impact angles was 2.1%, 3.4% and 1.8%, respectively. Following the analysis of the images, the Weber number (We = 2 \(\cdot\)\(\cdot\)\(R_{\mathrm{d}}\)\(\cdot\)\(U_{\mathrm{d}}\)\({}^{2}/\sigma\)), [PERSON] number (Oh = \(\mu\)\(/\)\((2\cdot\)\(R_{\mathrm{d}}\)\(\cdot\)\(\rho\)\(\cdot\)\(\sigma\))\({}^{0.5}\)), Reynolds number (Re = \(\rho\)\(\cdot\)\(2R_{\mathrm{d}}\)\(\cdot\)\(U_{\mathrm{d}}\)\(/\)\(\psi\)) and capillary number (Ca = \(\mu\)\(\cdot\)\(U_{\mathrm{d}}\)\(/\)\(\sigma\)) were calculated [51]. The  
Figure 1: Experimental setup scheme (**a**) and photo (**b**): 1—high-speed video camera; 2—copper capillary of vacuum pump; 3—vacuum pump; 4—syringe pump; 5—positioning mechanism; 6—particle holder (a needle with a flat tip); 7—detachable nozzle; 8—spotlight; 9—liquid supply capillary; 10—syringe; 11—liquid droplet; 12—air supply capillary; 13—container to collect liquid; 14—air compressor. Ohnesorge number reflects the ratio of viscous forces to the combined effect of inertial and surface tension forces. The Weber number is related to the ratio of inertial forces to the surface tension forces. Constructing droplet-particle collision regime maps in the We(Oh) system takes the effect of density, viscosity and surface tension of liquid into account [23]. The linear impact parameter was calculated allowing for the distance between the centers of mass of the particle and droplet: \(B=b/(R_{\text{d}}+R_{\text{p}})\). When establishing the regime boundaries, experimental points were plotted on the map. After that, the terminal or boundary points, characterizing each regime of the droplet interaction, were determined. Then a boundary connecting these points was plotted. If 95% of the points were within the boundary of a certain regime area, an approximation boundary line was drawn. The Weber and Ohnesorge numbers, as well as the linear impact parameter, were calculated. This was followed by producing regime maps in the B(We) coordinate system. The regime maps were plotted using the dimensionless impact parameter, since it also indirectly allows for the impact angle.