图即为所得乙基纤维素微球粉体的微观形貌、表面及其断面结构。从图中可以看出，所得粉体呈现不规则的形貌，其粒径分布约在100~500 nm之间。由于第一步乳化过程中，水相为乙酸乙酯的不饱和水溶液，因此在乳化的初始阶段，乙酸乙酯就开始溶于水相。而这就造成了油相液滴粘度的增加，从而在乳化初期就形成了刚性较强的油/水界面，这样油相液滴在高速剪切下的破坏就被抑制了。而所得粉体的不规则形貌就应当源于高粘度大尺寸油相液滴在高速剪切下的形变。此外，从图可以看出，所得粉体在其表面具有大量的开孔结构，而粉体断面的SEM照片也表明，所得粉体为多孔结构，且内部多为通孔结构。

The figure shows the microstructure, surface and cross section structure of the obtained ethylcellulose microsphere powder.  It can be seen from the figure that the obtained powder presents an irregular morphology, and its particle size distribution is about 100~500 nm.  Since the water phase in the first emulsification process is an unsaturated aqueous solution of ethyl acetate, ethyl acetate begins to dissolve in the water phase at the initial stage of emulsification.  This results in an increase in the viscosity of the oil droplets, resulting in the formation of a rigid oil/water interface at the initial stage of emulsification, so that the damage of the oil droplets under high-speed shear is suppressed.  The irregular morphology of the obtained powder should be due to the deformation of large size oil droplets with high viscosity under high-speed shear.  In addition, it can be seen from the figure that the obtained powder has a large number of open structures on its surface, and the SEM photos of the powder section also show that the obtained powder has a porous structure, and the internal structure is mostly through the hole.