Fabrication of raspberry-like polymethylsilsesquioxane microspheres mediated by tinny calcium carbonate particles

• Raspberry-like polymethylsilsesquioxane microspheres were fabricated.
• Tinny calcium carbonate particles acting as nucleation center
• Polymethylsilsesquioxane particles showed great increment in hydrophobicity.

The particle formation behavior of methyltrimethoxysilane (MTMS) was researched in the presence of a small amount of inorganic calcium carbonate particles. MTMS was first hydrolyzed in water under the catalyzation by hydrochloric acid to produce hydrolyzate and then neutralized by base sodium hydroxide. Under the neutral condition, the hydrolyzate of MTMS was mixed with a small amount of newly-prepared precipitation of calcium carbonate. Following this, hydrolytic polycondensation reaction catalyzed by adding ammonia to the mixture was conducted. The results show that polymethylsilsesquioxane (PMSQ) particles with raspberry-like morphology were obtained by this method, while those without addition of calcium carbonate are of smooth surface, which was confirmed by scanning electron microscopy (SEM) micrographs. The static water contact angles changed from 136.2 ± 0.9° of pure PMSQ particles with smooth surface to 146.3 ± 1.1° with raspberry-like morphology, showing a great increment in apparent hydrophobicity.

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