Stabilization of Aqueous MMA Emulsions Using Mixtures of Surfactants and Implications on MMA Miniemulsion Polymerizations

Abstract

Miniemulsion polymerization is a robust and simple method for manufacture of polymer nanoparticles. However, it is strongly dependent on the precursor monomer-in-water emulsion stability. Thus, the present study investigates the influence of concentration and combination of nonionic surfactants (resulting in different hydrophile-lipophile balances, HLB) on the stabilization of emulsions of methyl methacrylate in water. Backscattering profiles obtained with Turbiscan show that a combination of Tween80 and Span80 can grant the desired initial system stabilization, although the optimum HLB values depend on the amount of surfactant mixture. Miniemulsion polymerizations are then successfully performed with nonionic surfactant mixtures, providing high monomer conversion in less than 1 h and poly(methyl methacrylate) nanoparticles with average diameters ranging from 300 to 500 nm. Finally, it is observed that the addition of small amounts of an anionic surfactant to the surfactant mixture (10 wt.%) can be very beneficial for the process, allowing the control of reaction rates, the production of smaller nanoparticles with average diameters from 100 to 300 nm, and the enhanced stabilization of the final solid dispersion, while simultaneously keeping the concentration of ionic surfactants small.

The Influence of Glass Transition Temperature of PMMA-Based Nanoparticles on the Release Profile of Praziquantel as a Strategy for Controlling Drug Release

“…The negative values of the nanoparticles’ zeta potential was due to the sulfate group, present both in the initiator fragments and in the surfactant. This might represent a competitive advantage in some applications, since negatively charged nanoparticles can be used more successfully for drug delivery purposes because they reduce the adsorption of serum proteins, resulting in longer circulation half-lives. , Although it is not the scope of this work, our group also investigates the role of different surfactants in the miniemulsion polymerization of PMMA-based materials. , …”

“…53,54 Although it is not the scope of this work, our group also investigates the role of different surfactants in the miniemulsion polymerization of PMMA-based materials. 55,56 High encapsulation efficiencies were achieved in all analyzed systems, as shown in Table 1. The fact that PZQ is hydrophobic prevents it from migrating to the aqueous phase, where its solubility is extremely low (0.4 g L −1 ), 57 explaining the large encapsulation efficiencies even when more hydrophilic comonomers were present.…”