Microgel definition

Microemulsions are a convenient medium for preparing microgels in high yields and rather uniform size distribution. The name for these special emulsions was introduced by Schulman et al. [48] for transparent systems containing oil, water and surfactants, although no precise and commonly accepted definitions exist. In general a microemulsion may be considered as a thermodynamically stable colloidal solution in which the disperse phase has diameters between about 5 to lOOnm. 

For small microgels, like crosslinked particles of a microemulsion (diameter below 102 nm), the definition of the gel point is no longer clear. For instance, a... 

Particle of gel of any shape with an equivalent diameter of approximately 0.1 to 100 pm. Modified from [2]. The definition proposed here is recommended for its precision and because it distinguishes between a microgel and a nanogel. 

The microgel method (C) is advantageous over the multifunctional initiation (A) and termination (B) methods in that the product polymers may have a large number of arm chains, often exceeding 50 or sometimes 100. Because the microgellation process is statistical, however, there is by definition a distribution in the arm number in a particular polymer sample. In these regards, the polymer-linking method (C) is complementary with the multifunctional initiation (A) and the multifunctional termination (B). 

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