pH-induced solubility transition of sulfonamide-based polymers

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomaterials

Background:

• Designing pH-sensitive polymers is crucial for controlled release applications in biology.
• Sulfonamides offer tunable properties for polymer development.
• Understanding polymer solubility transitions is key for biomaterial design.

Purpose of the Study:

• To synthesize and characterize novel pH-sensitive polymers based on sulfonamide monomers.
• To investigate the influence of sulfonamide content on polymer pK(a) and solubility transitions.
• To explore the potential of these polymers in bio-related applications.

Main Methods:

• Modification of sulfonamides into polymerizable monomers.
• Synthesis of homopolymers and copolymers with N,N-dimethylacrylamide.
• Examination of pK(a) values for monomers, homopolymers, and copolymers.
• Investigation of pH-induced solubility and phase transition behavior using light transmittance.

Main Results:

• Sulfonamide monomers and polymers showed slightly higher pK(a) values compared to parent sulfonamides.
• Homopolymers exhibited solubility transitions at 85-90% ionization.
• Copolymers displayed sharp solubility transitions (0.2-0.3 pH units) that shifted to higher pH with increased sulfonamide content.
• Polymer precipitation was attributed to the balance of hydrophilicity/hydrophobicity.

Conclusions:

• Developed sulfonamide-based polymers demonstrate controllable pH-sensitivity.
• The tunable solubility transitions are influenced by sulfonamide content and ionization degree.
• These polymers hold promise for advanced bio-related applications requiring precise pH responsiveness.