Nitroxide-Mediated Radical Polymerization in Miniemulsion On the Basis of in Situ Surfactant Formation without Use of Homogenization Device

The effect of surface-active statistical copolymers in low-energy miniemulsion and RAFT polymerization

Study of the composition, lenght and chemical structure of surface-active statistical copolymers in low-energy miniemulsions.

Shape-Controlled Nanoparticles from a Low-Energy Nanoemulsion

Nanoemulsion technology enables the production of uniform nanoparticles for a wide range of applications. However, existing nanoemulsion strategies are limited to the production of spherical nanoparticles. Here, we describe a low-energy nanoemulsion method to produce nanoparticles with various morphologies. By selecting a macro-RAFT agent (poly(di(ethylene glycol) ethyl ether methacrylate-co-N-(2-hydroxypropyl) methacrylamide) (P(DEGMA-co-HPMA))) that dramatically lowers the interfacial tension between monomer droplets and water, we can easily produce nanoemulsions at room temperature by manual shaking for a few seconds. With the addition of a common ionic surfactant (SDS), these nanoscale droplets are robustly stabilized at both the formation and elevated temperatures. Upon polymerization, we produce well-defined block copolymers forming nanoparticles with a wide range of controlled morphologies, including spheres, worm balls, worms, and vesicles. Our nanoemulsion polymerization is robust and well-controlled even without stirring or external deoxygenation. This method significantly expands the toolbox and availability of nanoemulsions and their tailor-made polymeric nanomaterials.

Miniemulsion photopolymerization in a continuous tubular reactor: particle size controlviamembrane emulsification

Synthesis of polymeric nanoparticles of adjustable size in the submicron-range 200–950 nm has been conductedviamembrane emulsification combined with photoinduced miniemulsion polymerization in a continuous tubular flow reactor.

Block copolymer synthesis by controlled/living radical polymerisation in heterogeneous systems

We review the range of CLRP-controlled syntheses of block copolymer particles in dispersed systems, which are being exploited to create new opportunities for the design of nanostructured soft materials.

Radical polymerization of miniemulsions induced by compressed gases

Pressurization of a macroemulsion comprising a vinyl monomer/water/surfactant can result in formation of a transparent miniemulsion without use of high energy mixing, suitable for synthesis of polymeric nanoparticlesviaminiemulsion polymerization.

Rate-Enhanced Nitroxide-Mediated Miniemulsion Polymerization

A novel approach is presented whereby nitroxide-mediated radical polymerization (NMP) is conducted in an aqueous heterogeneous system at an initial polymerization rate an order of magnitude greater than the corresponding bulk system, accompanied by an improvement in the level of control over the molecular weight distribution. NMP of styrene mediated by N-tert-butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)] nitroxide (SG1) at 90 °C was performed in a miniemulsion with exceptionally small particles of number-average diameter ∼10 nm, generated by ultrasonication combined with in situ surfactant formation. The results are discussed in terms of the effects of compartmentalization, nitroxide partitioning (exit/entry), and a rate-enhancing effect of oleic acid. These findings illustrate that it is possible to significantly improve the performance of an NMP process by the exploitation of intrinsic effects of heterogeneous systems.

Reversible Addition–Fragmentation Chain Transfer (RAFT) Polymerization in Miniemulsion Based on In Situ Surfactant Generation

Reversible addition–fragmentation chain transfer (RAFT) polymerization of styrene has been implemented in aqueous miniemulsion based on the in situ surfactant generation approach using oleic acid and potassium hydroxide in the absence of high energy mixing. The best results were obtained using the RAFT agent 3-benzylsulfanyl thiocarbonyl sufanylpropionic acid (BSPAC), most likely as a result of the presence of a carboxylic acid functionality in the RAFT agent that renders it surface active and thus imparts increased colloidal stability. Stable final miniemulsions were obtained with no coagulum with particle diameters less than 200 nm. The results demonstrate that the RAFT miniemulsion polymerization of styrene employing the low energy in situ surfactant method is challenging, but that a system that proceeds predominantly by a miniemulsion mechanism can be achieved under carefully selected conditions.