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采用分子动力学模拟方法研究了水滴在多面体低聚倍半硅氧烷(H-POSS)固体表面的润湿性能,H-POSS分子和水分子分别采用COMPASS力场和SPC力场模型。模拟得到H-POSS基体密度为1.84g/cm~3,且X射线衍射模拟发现基体具有明显衍射峰,表现出晶体特性,说明COMPASS力场适用于H-POSS基体的构建与研究。H-POSS表面水接触角的模拟值为104.9°,具有疏水性能。通过直接水解法由三氯硅烷(HSiCl_3)实验合成出H-POSS样品,傅立叶红外表征(FT-IR)发现,在2260、1142和871cm~(-1)波数位置出现吸收峰,证实了所合成的样品为H-POSS。其表面水接触角的实验值为109.3°,与模拟值的相对误差仅为4%,说明分子动力学方法可应用于计算H-POSS材料表面润湿性。模拟结果还表明体系温度影响H-POSS材料的表面润湿性,增大体系温度,表面疏水性能降低。
Molecular dynamics simulation was used to study the wettability of droplets on the solid surface of polyhedral oligomeric silsesquioxane (H-POSS). The COMPASS and SPC force fields models were used for H-POSS molecules and water molecules respectively. The density of H-POSS matrix was 1.84g / cm ~ 3. The X-ray diffraction simulation showed that the matrix has obvious diffraction peaks and shows the crystal properties. It is shown that the COMPASS force field is suitable for the construction and research of H-POSS matrix. H-POSS surface water contact angle of the simulation value of 104.9 °, with hydrophobic properties. H-POSS samples were synthesized by direct hydrolysis from trichlorosilane (HSiCl_3). Fourier transform infrared spectroscopy (FT-IR) showed that the absorption peaks appeared at the wave numbers of 2260, 1142 and 871cm -1, The sample is H-POSS. The experimental value of surface water contact angle is 109.3 °, and the relative error of simulation value is only 4%, indicating that the molecular dynamics method can be applied to calculate the surface wettability of H-POSS material. The simulation results also show that the system temperature affects the surface wettability of H-POSS material, increases the system temperature and decreases the surface hydrophobicity.