Controlled stable free radical emulsion polymerization processes

A heterogeneous free radical polymerization process comprising:

• (a) forming a heterogeneous mixture comprising water, a first amount of a first polymerizable monomer, an initiator capable of generating an initiating radical, and a control agent, the initiator and the first polymerizable monomer being present in the mixture in a ratio that is in the range of from about 1:10 to about 1:1000, the control agent being characterized by the general formula:
• wherein X is a moiety that is capable of destabilizing the control agent on a polymerization time scale;
• and
• each R1, R2 and R3 is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, silyl, boryl, phosphino, amino, thio, and seleno;
• (b) heating the mixture at a temperatures of about 100° C. or less for a time sufficient to form a polymer, such that substantially no unreacted initiator remains in the mixture;
• and
• (c) adding a second amount of the first polymerizable monomer to the mixture and heating the mixture to continue propagation of the polymer.