A deeper insight into the evaluation of water-in-oil amicroemulsion templated samarium sulfide nanospheres: exploring its role in pickering emulsion formulation for photocatalytic dye degradation and synthesis of PANI@Sm 2 S 3 nanocomposites.

This study examines the effectiveness of W/O microemulsion-mediated Sm2 S3 nanospheres in pickering emulsion-based crystal violet (CV) dye degradation and PANI@Sm2 S3 nanocomposite synthesis. The evaluation of nanospheres inside the core of reverse micelles was performed through DLS, TEM and FESEM analyses. The formation of nanospheres involve two phases: a nucleation phase (5-30 min) and growth phase (30-120 min). Through in situ hydrophobization of negatively charged (with a zeta value of -4.47 mV at neutral pH) Sm2 S3 nanoparticles (0.1 wt%) with a suitable amount of a cationic CTAB surfactant, a stable O/W pickering emulsion was developed. 0.1 wt% Sm2 S3 in situ hydrophobized with 2.7 mM CTAB offered a stable pickering emulsion with a diameter of 23 μm after 1 day of storage. This pickering emulsion improves the local concentration of CV by efficiently encapsulating dye molecules inside the core of emulsion droplets. Therefore, dye molecules get numerous opportunities to interact with the Sm2 S3 photocatalyst and efficiently degrade. The pickering emulsion stabilised by 0.1 wt% of Sm2 S3 nanoparticles in situ hydrophobized with 2.7 mM of CTAB results in almost 100% degradation. Moreover, using only solid Sm2 S3 (having wt% of 0.025 or 0.075) as a pickering stabiliser, new PANI@Sm2 S3 spherical nanocomposites were synthesised via pickering emulsion polymerization. The formation of PANI@Sm2 S3 composites was identified via UV-vis, IR, and 1 H-NMR investigations. The analysis of FESEM images showed that the amount of nanoparticles used in the dispersion (for 0.025 wt%, 35 nm and 0.075 wt%, 29 nm) strongly influences the size and shape of the composites.