silica is hydrophilic mainly because the surface of silica silica is surrounded by silicon hydroxyl groups, so the surface modification of silica silica is relatively easy. The selected modifier is generally the chemical substance that is easy to react with the hydroxyl group on the surface of silica, and the modification effect of organic matter is better when it is used as modifier.
Commonly used modifiers are the following: (1) organosilicate halogen compounds: such as dimethyl dichlorosilane, trimethyl chlorosilane. (2) Siloxane organic compounds: such as polydimethylsiloxane (PDMS), hexamethyldisiloxane (MM), octaethyltrisiloxane (MDM). (3) Alcohol compounds: such as butanol, amyl alcohol, straight chain heptanol, etc. (4) Silane compounds: such as hexamethyldisilane, etc. (5) Organic polymers: such as polyvinyl alcohol. (6) Silane coupling agent class: including hexamethylsilazane, hexamethylsilazane, vinyl ethoxy silane, trimethylethoxy silane, methyl trimethoxy silane, etc.