中文摘要：

在超声辅助、氨水催化条件下，以十六烷基三甲氧基硅烷为正硅酸乙酯的共前驱体，采用溶胶-凝胶法制备了疏水纳米二氧化硅。采用纳米粒度仪、FTIR、TG-DTA等分析方法表征了疏水纳米二氧化硅，测定表明该粒子直径集中在30-50nm，疏水性保持温度为244℃。在商用石材防护涂料Coesol中添加疏水纳米二氧化硅，随着纳米粒子质量分数的增加，石材表面疏水程度增强，当纳米粒子质量分数大于等于1．1％时，石材表面呈超疏水性；而毛细吸水量和水蒸气透气性却随着纳米粒子质量分数的增加而减小。

英文摘要：

Hydrophobic silica nanoparticles have been prepared in ammonium hydroxide using ultrasonication by Sol-gel process. An alkyltriethoxysilane derivative, hexdecyltrimethoxysilane, was co-condensed with tetraethoxyorthosilicate to produce the hydrophobic silica nanoparticles. The chemical structure was studied by particle size analyzer, FTIR and TG-DTA. The results show that the nanoparticles＇ diameter is about 30-50nm and the hydrophobie nature of the nanoparticles is maintained at 244℃. The modification of the commercial siloxane（Coesol） protective composition by the addition of hydrophobic silica nanoparticles enhances its protective efficiency and increases limestone surface hydrophobicity. The extent of surface hydropbobization enhances with nanoparticle concentration increasing, while water vapor permeability and water capillary absorption decrease. And the superhydrophobic effect is achieved at 1.1 % of nanoparticles for limestone treated with the modified composition.