Hybrid nanoparticles obtained from mixed mesoglobules

- Mixed mesoglobules from PNIPAM and PIPOX were prepared.
- PNIPAM effectively prevents the crystallization of PIPOX in mesoglobules.
- Heating protocol significantly influences the morphology of mesoglobules.
- Nanoparticles were obtained by covering the mesoglobules with cross-linked shell.
- Hybrid thermoresponsive nanoparticles exhibit good colloidal stability.

This article describes the preparation and characterization of mixed mesoglobules from two thermoresponsive polymers: poly(N-isopropyl acrylamide) (PNIPAM) and poly(2-isopropyl-2-oxazoline) (PIPOX) and their coating with a crosslinked shell to obtain hybrid nanoparticles. The variations in dimensions and stability of the mixed mesoglobules prepared with different compositions (20/80, 50/50 and 80/20 PIPOX-to-PNIPAM weight ratios) and using different heating protocols (gradual and abrupt heating) indicate their sensitivity to both parameters. Unlike neat PIPOX particles as well as PIPOX-rich ones, the mixed particles with higher PNIPAM content (20/80 and 50/50) exhibit a fully reversible coil-to-globule phase transition implying that in these cases PNIPAM effectively prevents the crystallization of PIPOX. The mesoglobules were covered with a cross-linked polymeric shell by seeded radical copolymerization of NIPAM and N,N-methylenbisacrylamide. The resulting hybrid nanoparticles retain their stability and do not disintegrate at low temperatures.