表面活性剂分子设计(续完)

Surfactants at the design limit

3 硅表面活性剂 硅表而活性剂通常也被称为硅氧烷表而活性剂，它是以全甲基化的硅氧烷为疏水主链，在其中间位或端位接一个或多个有机极性基团而构成的一类表面活性剂。常见的硅表而活性剂结构有3种：耙型（又叫梳型或接枝型）、ABA型（B代表硅氧烷部分）和三硅氧烷型。

This article analyzes how the individual structural elements of surfactant molecules affect surface properties, in particular. the point of reference defined by the limiting surface tension at the aqueous cmc, γcmc. Particular emphasis is given to how the chemical nature and structure of the hydrophobic tails influence γcmc By comparing the three different classes of surlhctants, fluorocarbon, silicone, and hydrocarbon, a generalized surface packing index is introduced which is independent of the chemical nature of the surthctants. This parameler Ф represents the volume fi-action of surthctant chain fragments in a surface film at the aqueous cmc. It is shown that Фcmc is a useful index tbr understanding the limiting surface tension of surfactants and can be useful for designing new superefficicnt surfactants.