Fabrication of polyelectrolyte multilayered nano-capsules using a continuous layer-by-layer approach

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• The layer-by-layer (LbL) assembly is a versatile technique for creating multilayered polymeric structures.
• Traditional LbL fabrication of nano-capsules is time-consuming and inefficient at larger scales due to repeated washing and centrifugation steps.

Purpose of the Study:

• To develop a continuous, scalable method for fabricating polyelectrolyte nanocapsules.
• To improve the efficiency and reduce the fabrication time for multilayered nanocapsules.

Main Methods:

• Utilized a tubular flow reactor for continuous synthesis of polyelectrolyte nanocapsules.
• Employed calcium phosphate core nanoparticles and sequential adsorption of oppositely charged polyelectrolytes in a flow system.
• Controlled polyelectrolyte dosage to ensure efficient adsorption and minimize residual polymer in solution.

Main Results:

• Achieved continuous production of tens of milligrams of nanocapsules per hour.
• Demonstrated stable nanocapsule formation with zeta potentials consistently above ±25mV, indicating charge reversal at each layer deposition.
• Successfully removed calcium phosphate cores using acid dissolution to yield hollow nanocapsules.

Conclusions:

• The continuous flow approach offers a significant advancement for scalable nanocapsule fabrication.
• This method overcomes the limitations of batch-based LbL processes, enabling efficient and rapid production.
• The resulting nanocapsules exhibit stability and can be readily functionalized for various applications.