Polymerization of alkyl methacrylate nanoemulsions made by the phase inversion temperature method

Polymer nanoparticles from low-energy nanoemulsions for biomedical applications

The formulation of nanoemulsions by low-energy strategies, particularly by the phase inversion composition method, and the use of these nanoemulsions as templates for the preparation of polymer nanoparticles for biomedical applications are reviewed. The methods of preparation, nature of the components in the formulation, and their impact on the physicochemical properties, drug loading, and drug release are discussed. We highlight the utilization of ethyl cellulose, poly(lactic-co-glycolic acid), and polyurethane/polyurea in the field of nanomedicine as potential drug delivery systems. Advances are still needed to achieve better control over size distribution, nanoparticle concentration, surface functionalization, and the type of polymers that can be processed.

Synthesis and characterization of butyl acrylate-co-poly (ethylene glycol) dimethacrylate obtained by microemulsion polymerization

The synthesis and characterization of copolymers of n-Butyl Acrylate (BA) and Poly(ethylene glycol) dimethacrylate (PEGDMA) were realized by microemulsion. In this synthesis, the relation of PEGDMA 10, 20, 30, 40 and 50% wt with respect to BA was changed. The copolymers obtained were characterized by the determination of conversions (gravimetry), infrared spectroscopy: Fourier transform (FTIR), dynamic light scattering (DLS), thermogravimetry (TGA) and differential scanning calorimetry (DSC). The results confirmed the synthesis of BA-co – PEGDMA copolymers by the identification of characteristic FTIR bands and which determined the glass transition temperature of the copolymers. The conversions were found in the range of 85% to 90%. Within the stability of the produced latex, it was observed that at 10% and 30% wt. of PEGDMA the systems were stable, but when more PEGDMA was added up 40% to 50% wt., the system became unstable. The stability of produced latexes depends on the PEGDMA contents and this must be less than 30% wt.; meanwhile the PEGDMA content greater than 30% wt. leads to unstable latexes, forming clots. Copolymers showed single glass transition temperatures between −53.37°C and −16.58°C, depending on the composition of PEGDMA in the copolymers. Resulting in the different arrangements of units of PEGDMA along in the chain affected the thermal properties of the final copolymers.

Polymer nanoparticle sizes from dynamic light scattering and size exclusion chromatography: the case study of polysilanes

Dynamic light scattering (DLS) and size exclusion chromatography (SEC) are among the most popular methods for determining polymer sizes in solution. Taking dendritic and network polysilanes as a group of least soluble polymer substances, we critically compare and discuss the difference between nanoparticle sizes, obtained by DLS and SEC. Polymer nanoparticles are typically in poor solution conditions below the theta point and are therefore in the globular conformation. The determination of particle sizes in the presence of attractive interactions is not a trivial task. The only possibility to measure, aggregation-free, the true molecular size of polymer nanoparticles in such a solution regime, is to perform the experiment with a dilute solution of globules (below the theta point and above the miscibility line). Based on the results of our polysilane measurements, we come to a conclusion that DLS provides more reliable results than SEC for dilute solutions of globules. General implications for the size measurements of polymer nanoparticles in solution are discussed.