UV-cross-linkable multilayer microcapsules made of weak polyelectrolytes.

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Layer-by-layer (LbL) fabrication is a versatile method for creating multilayered materials.
• UV-responsive polymers offer tunable properties upon light exposure.
• Controlling microcapsule permeability is crucial for encapsulation and release applications.

Purpose of the Study:

• To fabricate UV-responsive microcapsules using weak polyelectrolytes functionalized with benzophenone (BP).
• To investigate the effect of UV irradiation on microcapsule size and permeability.
• To establish a method for stabilizing microcapsule shells via UV-induced cross-linking.

Main Methods:

• Fabrication of weak polyelectrolyte microcapsules via the layer-by-layer (LbL) technique.
• Modification of microcapsules with UV-responsive benzophenone groups.
• Exposure to UV light (5 mW/cm(2)) to induce shrinkage and cross-linking.
• Encapsulation of fluorescence-labeled dextran molecules.

Main Results:

• UV irradiation caused rapid microcapsule shrinkage within minutes.
• Shrinkage modulated capsule permeability, allowing for non-thermal encapsulation of dextran molecules.
• UV-induced cross-linking effectively tightened and stabilized the capsule shells.
• Stabilization preserved the inherent pH-responsive properties of the polyelectrolyte multilayers.

Conclusions:

• UV-responsive benzophenone-modified microcapsules offer a novel platform for controlled encapsulation.
• The LbL technique combined with UV-triggered cross-linking provides a swift and reliable method for shell stabilization.
• This approach enables precise control over capsule permeability for advanced material applications.