Control of the Water Pool Size in Reverse Microemulsions

CONTROL OF THE WATER POOL SIZE IN REVERSE MICROEMULSIONS 

In a reverse microemulsion, the water pool diameter becomes very important as it can control the usability of the pool as, for example, a nanoreactor. This is therefore directly relevant to particle synthesis, i.e. controlling the particle-forming reactions and the particle size though there are many examples where the average pool and particle diameters have not been found to be exactly linked by proportionality. 

What are the factors that might control the water pool size It has been found by many workers that the most important controlling factor is the molar ratio w = [water] /[surfactant] and the nature of the continuous phase may not play a very significant role. Kotlarchyk etal. [148] studied the system NaA0T/n-decane/D20 by small-angle neutron scattering and proposed a relationship  

Vh = volume of the water-penetrated portion of a single AOT head-group () = area per AOT head-group on the water-core surface. 

Assumptions made for proposing the above relationship were that (i) water penetrates into the AOT head-group region, (ii) AOT molecules form a single layer on the droplet surface, and (iii) a i is a constant. It was clearly shown that for a given temperature, R increased systematically with X further, the parameters a ) and Vy were found to be dependent on temperature, which had an obvious effect on the water pool radius. 

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