Study of emulsion polymerization stabilized by amphiphilic polymer nanoparticles

Synthesis and self-assembly of polyethersulfone-based amphiphilic block copolymers as microparticles for suspension immunosensors

Polyethersulfone (PES) based amphiphilic block copolymer has been synthesized and transformed into immunological microparticles via confined emulsion self-assembly and surface biomodification, opens the in-vitro diagnostic application of PES.

The research about microscopic structure of emulsion membrane in O/W emulsion by NMR and its influence to emulsion stability

PURPOSE

This paper discussed the influence of microstructure of emulsion membrane on O/W emulsion stability.

METHODS

O/W emulsions were emulsified with equal dosage of egg yolk lecithin and increasing dosage of co-emulsifier (oleic acid or HS15). The average particle size and centrifugal stability constant of emulsion, as well as interfacial tension between oil and water phase were determined. The microstructure of emulsion membrane had been studied by (1)H/(13)C NMR, meanwhile the emulsion droplets were visually presented with TEM and IFM.

RESULTS

With increasing dosage of co-emulsifier, emulsions showed two stable states, under which the signal intensity of characteristic group (orient to lipophilic core) of egg yolk lecithin disappeared in NMR of emulsions, but that (orient to aqueous phase) of co-emulsifiers only had some reduction at the second stable state. At the two stable states, the emulsion membranes were neater in TEM and emulsion droplets were rounder in IFM. Furthermore, the average particle size of emulsions at the second stable state was bigger than that at the first stable state.

CONCLUSIONS

Egg yolk lecithin and co-emulsifier respectively arranged into monolayer and bilayer emulsion membrane at the two stable states. The microstructure of emulsion membrane was related to the stability of emulsion.

Pickering polymerization of styrene stabilized by starch-based nanospheres

Pickering polymerization of styrene stabilized by starch-based nanospheres to synthesize composite particles with different morphologies is reported.

Role of geometry and amphiphilicity on capillary-induced interactions between anisotropic Janus particles

We study the capillary interactions between ellipsoidal Janus particles adsorbed at flat liquid-fluid interfaces. In contrast to spherical particles, Janus ellipsoids with a large aspect ratio or a small difference in the wettability of the two regions tend to tilt at equilibrium. The interface deforms around ellipsoids with tilted orientations and thus results in energetic interactions between neighboring particles. We quantify these interactions through evaluation of capillary energy variation as a function of the spacing and angle between the particles. The complex meniscus shape results in a pair interaction potential which cannot be expressed in terms of capillary quadrupoles as in homogeneous ellipsoids. Moreover, Janus ellipsoids in contact exhibit a larger capillary force at side-by-side alignment compared to the tip-to-tip configuration, while these two are of comparable magnitude for their homogeneous counterparts. We evaluate the role of particles aspect ratio and the degree of amphiphilicity on the interparticle force and the capillary torque. The energy landscapes enable prediction of micromechanics of particle chains, which has implications in predicting the interfacial rheology of such particles at fluid interfaces.