Preparation and characterization of low dispersity anionic multiresponsive core-shell polymer nanoparticles

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Core-shell polymer nanoparticles offer versatile platforms for advanced applications.
• Stimuli-responsive polymers enable dynamic control over material properties.
• Anionic nanoparticles are crucial for biological and environmental applications.

Purpose of the Study:

• To synthesize anionic multistimuli responsive core-shell polymer nanoparticles with controlled charge distribution.
• To investigate the influence of comonomer type (acrylic acid vs. methacrylic acid) on nanoparticle properties.
• To demonstrate the tunability of particle size, phase transition temperature, and aggregation state via external stimuli.

Main Methods:

• Core-shell nanoparticles were synthesized using a poly(methyl methacrylate) (PMMA) core and a cross-linked poly(N-isopropyl acrylamide) (PNIPAM) shell.
• Acrylic acid (AA) or methacrylic acid (MA) was incorporated as a comonomer in the PNIPAM shell to vary charge distribution.
• Particle characteristics were modulated by adjusting temperature, pH, and ionic strength.

Main Results:

• Anionic nanoparticles with low size dispersity were successfully prepared.
• Different charge distributions were achieved using AA (outer shell) versus MA (inner shell) comonomers, while maintaining the same total charge.
• Particle volume phase transition temperature (T(VPT)) and aggregation were effectively tuned by pH, ionic strength, and temperature, demonstrating stimuli-responsiveness.

Conclusions:

• The synthesized core-shell nanoparticles provide a versatile platform for stimuli-responsive applications.
• Charge distribution within the nanoparticle shell significantly impacts T(VPT) and responsiveness.
• These tunable nanoparticles hold promise for advanced sensors, medical diagnostics, and environmental remediation.