Preparation and characterization of starch nanoparticles in ionic liquid-in-oil microemulsions system

• A novel ionic liquid microemulsion had been prepared.
• The formation of IL/O microemulsion was confirmed by UV–vis spectrophotometry and DLS analysis.
• Starch nanoparticles were prepared through 3 h IL/O microemulsion-crosslinking reaction.
• SEM data revealed that starch nanoparticles showed aggregation or cluster formation.
• Starch nanoparticles with a mean diameter of 96.9 nm were confirmed by the results of DLS.

A novel ionic liquid microemulsion consisting of 1-octyl-3-methylimidazolium acetate ([Omim]Ac, an ionic liquid), native corn starch, surfactant TX-100, 1-butanol and cyclohexane was prepared. The ionic liquid-in-oil (IL/O), bicontinuous, and oil-in-ionic liquid (O/IL) microregions of the microemulsions were identified by conductivity measurements. The formation of IL/O microemulsion was confirmed by UV–vis spectrophotometry using the methyl orange (MO) as absorption probes and dynamic light scattering (DLS) analysis. Starch nanoparticles were prepared with epichlorohydrin as crosslinker through 3 h IL/O microemulsion-crosslinking reaction at 50 °C. The results of Fourier transform infrared spectroscopy (FTIR) demonstrated the formation of crosslinking bonds in starch molecules. Scanning electron microscope (SEM) data revealed that starch nanoparticles showed aggregation or cluster formation. Starch nanoparticles with a mean diameter of 96.9 nm and narrow size distribution were confirmed by the results of DLS.