Tunable pH-Responsive Chitosan-Poly(acrylic acid) Electrospun Fibers

Area of Science:

• Polymer Science
• Materials Science
• Biomaterials Engineering

Background:

• Chitosan (Cs) and poly(acrylic acid) (PAA) are widely used polymers.
• Understanding their complexation under flow is crucial for material design.
• The degree of deacetylation (DD) of chitosan influences its properties.

Purpose of the Study:

• To investigate the macromolecular organization of Cs/PAA systems under elongational flow.
• To characterize the pH-triggered behavior of Cs/PAA complexes.
• To evaluate the influence of chitosan's degree of deacetylation on system properties.

Main Methods:

• Formation of Cs/PAA nanofibers via elongational flow.
• pH-dependent studies of polyelectrolyte complexation.
• Rheological measurements to assess viscosity and mechanical properties.
• Swelling degree and elastic modulus analysis.

Main Results:

• Cs/PAA nanofibers formed via polyelectrolyte complexation in fluid media at specific pH.
• A pH-triggered system with reversible swelling (3 orders of magnitude) and elastic modulus changes (2 orders of magnitude).
• Swelling and elastic modulus were sensitive to the degree of deacetylation (DD) of Cs.
• Increased DD of Cs decreased viscosity in pure Cs and Cs/PAA solutions due to electrostatic repulsion and altered intermolecular interactions.

Conclusions:

• Cs/PAA systems form pH-responsive materials with tunable properties.
• The degree of deacetylation of chitosan is a critical parameter controlling material behavior.
• These findings have implications for developing advanced functional materials and hydrogels.