A non-crystallization-driven strategy for the preparation of non-spherical polymeric nanoparticles

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Fabricating non-spherical nanostructures via synthetic polymer self-assembly, mimicking biological forms, remains a significant challenge.
• Existing methods often rely on crystallization-driven forces, limiting the diversity of achievable structures.

Purpose of the Study:

• To develop a novel strategy for creating precisely defined, non-spherical polymer nanostructures using polymerization-induced self-assembly (PISA).
• To demonstrate the versatility of this method in producing various advanced hierarchical architectures.

Main Methods:

• Utilized styrene and methacrylic monomers with a maleamic acid-α-methyl styrene copolymer macroinitiator for PISA.
• Employed specific solvent conditions (50 wt% ethanol in water) and monomer ratios (styrene to 2-hydroxyethyl methacrylate at 3:1) to induce non-spherical morphology.
• Characterized nanostructures using wide-angle X-ray scattering (WAXS) and elucidated formation mechanisms via density functional theory (DFT) calculations.

Main Results:

• Successfully transformed spherical micelles into cubic nanoparticles (50–200 nm edge length) through a PISA process.
• Observed a unique self-assembly pathway involving vesicles encapsulating nascent cubes, which later emerged as well-defined cubic nanoparticles.
• WAXS analysis confirmed the absence of crystalline structures in the fabricated cubic nanoparticles.
• Demonstrated the method's universality by synthesizing other non-spherical shapes, including rectangles, fusiform platelets, and triangular pyramids, using different monomers.

Conclusions:

• The developed PISA strategy offers a robust and versatile approach for fabricating complex, non-spherical polymer nanostructures without crystallization.
• This method provides a pathway to mimic biological nanostructures and opens avenues for designing advanced materials with tailored hierarchical architectures.