## 3 Results and Discussion
### Compatibility of MPNTS  
Compatibility is the basis of the application of surfactants, and the surface properties of ordinary hydrosiloxanes in aqueous solution are limited [34]. In order to improve the use of various surfactants, in the daily preparation of formulations, the form of compounding is often used to integrate various functions of surfactants into one system, so as to achieve a synergistic effect. Surface property of a single surfactant system is often not optimal. In contrast, the adsorption of multiple surfactants in a complex system is considered synergistic, meaning that a small number of adsorbed surfactants can induce significant, ordered changes in oil molecules on the interface. These molecules will attract more surfactants to adsorb. Therefore, two or more surfactants with low affinity can exert better surface properties under the synergistic effect in the same water or oil system. [PERSON] et al. [35; 36] discussed these points in detail using anionic, cationic, and nonionic surfactants. This present paper primarily discusses the formation of complex systems of MPNTS and different types of surfactants, and it studies their synergistic properties in the binary system while predicting the solubilization ability of MPNTS. Compatibility experiments with common cationic surfactants, anionic surfactants, and nonionic surfactants were carried out with MPNTS. The effects of the mass ratio of MPNTS to cationic surfactants on the surface tensions of the aqueous solutions. are shown in Figure 6a. The cationic surfactants used are dodecyl trimethyl ammonium chloride (1231), dodecyl dimethyl benzyl ammonium chloride (1227) and dioctyl dimethyl ammonium chloride (D0821), respectively. The results showed that the surface tensions of 1231, 1227, and D0821 aqueous solutions were 53.13 mN/m, 40.18 mN/m, and 25.31 mN/m, respectively, before cationic surfactants were added to MPNTS. With the addition of MPNTS, the surface tension of the system was significantly reduced, and as the ratio of the two increases, the surface tension decreased. The specific performances were that the surface tension decreases most obviously when the mass ratio of MPNTS to cationic surfactants were at 1:5 and 1:10, showing a strong synergistic effect, and finally the surface tensions of the entire system would be reduced to near the surface tension of aqueous solutions of single component MPNTS. The anionic surfactant was sodium dodecyl benzene sulfonate (LAS). The effects of the mass ratio of MPNTS to anionic surfactant on the surface tensions of the aqueous solutions were shown in Figure 6b. The results showed that the surface tension of the LAS-MPNTS compound system aqueous solutions decreased from 36.20 mN/m of the single component to about 20 mN/m, which further reflected the synergistic effect of MPNTS. The effects of the mass ratio of MPNTS to nonionic surfactant (EN70) on the surface tensions of the aqueous solutions were shown in Figure 6b. The surface tension of nonionic surfactant aqueous solutions was 27.57 mN/m, and the same synergism occurs when MPNTS was added. According to the above results, it can be inferred that most surfactants with surface tension greater than MPNTS (18.68 mN/m) can be well compounded with it and show excellent synergistic effect, thus greatly increasing the surface properties of the system. Research indicates that the surfactant system in the binary complex exhibits superior surface activity compared to a single surfactant, with a synergistic effect in reducing surface tension, critical micelle concentration, and mixed micelle formation in the solution under consideration. The synergistic effect of formulation enables the attainment of maximum cleaning, wetting, or solubilizing power with a reduced amount of surfactant, thereby minimizing costs and promoting environmental protection [37]. The above results showed that MPNTS had significant synergistic effect with cationic, anionic. and nonionic surfactants, respectively.