A composite coating with self-embrittlement was prepared using SiO2-modified 3-aminopropyltrimethoxysilane and a solution of random copolymer P(PMMA-co-PMAA-co-PTFEMA). The structures and properties of the composite emulsions were determined using Fourier transform infrared spectroscopy, thermogravimetry, X-ray diffractometry, and transmission electron microscopy. The results indicate that the self-embrittlement morphology of the coating can be controlled by adjusting the ratio of MMA/MAA in the random copolymer. Furthermore, the coating exhibits a good decontamination effect on simulated radioactive dust (doped with elemental K).