Polyglycerol Surfmers and Surfactants for Direct and Inverse Miniemulsion

Poly(ethylene glycol)-based surfactants are a prominent example for nonionic surfactants. Poly(glycerol) (PG) is discussed as a polyfunctional alternative, however, it is not yet used to stabilize miniemulsions. The anionic polymerization of glycidyl ethers is used to prepare surfactants for direct or inverse emulsions and ambident surfactants by adjusting the copolymer composition. Orthogonal-protected poly(glycerol) block copolymers, using ethoxyethyl glycidyl ether and allyl glycidyl ether (AGE) or tert-butyl glycidyl ether (tBuGE), are synthesized. After cleavage of the acetal groups, these all-polyglycerol surfactants (PG-b-PtBuGE) or multifunctional surfmers (PG-b-PAGE), are used in direct and inverse miniemulsion polymerizations. Polystyrene nanoparticles are obtained by free-radical miniemulsion polymerization, in which the allyl-functionalized copolymers act as surfmer. In inverse miniemulsion, hydroxyethyl starch nanocarriers are synthesized with PG-b-PAGE as surfmer, transferred into aqueous PG-b-PtBuGE solution, and functionalized by thiol–ene addition. The PG-b-PtBuGE with equal block length ratio is used as a surfactant for direct and inverse miniemulsions. With the PG being covalently bound to the nanocarriers, a desorption during protein adsorption does not occur. It is believed that these surfactants are promising alternatives to conventional surfactants with additional functionality.