Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

Area of Science:

• Materials Science
• Analytical Chemistry
• Polymer Chemistry

Background:

• Immobilization of oxygen-sensitive probes (OSPs) is critical for optical dissolved oxygen (DO) sensor performance and longevity.
• Developing robust encapsulation methods is key to preventing probe leakage and ensuring sensor stability.

Purpose of the Study:

• To fabricate oxygen-sensitive polymeric nanocapsules (NCs) using a novel polymerization technique.
• To characterize the nanocapsules and evaluate their suitability for optical DO sensing applications.

Main Methods:

• Interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization was used to encapsulate fluorescent dyes within a crosslinked fluorinated polymer shell.
• Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and fluorescent spectroscopy were employed for characterization.
• An optical DO sensor was constructed using the fabricated nanocapsules.

Main Results:

• Precisely tunable dye-encapsulated capacity (0-1.3 wt%) without self-quenching.
• Crosslinked fluorinated polymer shell exhibited high gas permeability and prevented dye leakage in aqueous and organic solvents.
• The optical DO sensor demonstrated high sensitivity (7.02), rapid response time (~14.3 s), full reversibility, and 3-month operational stability.
• Sensor performance was unaffected by pH variations (2-12).

Conclusions:

• The developed oxygen-sensitive polymeric nanocapsules provide a stable and efficient platform for optical DO sensing.
• These nanocapsules are particularly suitable for long-term online DO monitoring in both aqueous and organic solvent systems.
• The fabrication method offers precise control over dye loading and ensures probe integrity.