The Monolayer and its Determination

A number of relatively simple methods are used to find out what the apparent mono-layer level is. The most common ones are described in the rest of this section. 

The amount of additive needed to cover unit area of surface has been determined experimentally, or calculated from molecular models, for many common additives. This enables the theoretical mono-layer amount to be calculated, if the specific surface area of the filler is known. As described previously, factors such as surface irregularity and additive orientation have to be taken into account. The reported coverage for a number of common surface modifiers is given in Table 4.2. As demonstrated by the data for the two vinyl silanes, the nature of the alcohol has a major effect on the covering power of these additives. 

Modifier Coverage (m of available surface, per gram of additive) 

2 Viscosity Reduction or Settling Volume of a Suspension of the Filler in a Simpie Organic Liquid 

It is frequently observed that a minimum viscosity or settling volume is reached at about the mono-layer level. 

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