Physically Crosslinked Poly(methacrylic acid)/Gelatin Hydrogels with Excellent Fatigue Resistance and Shape Memory...

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Hydrogels require robust mechanical properties to withstand dynamic stresses.
• Achieving high strength comparable to biological tissues and plastics often necessitates harmful chemical crosslinkers.
• Utilizing hydrogen bonds as sacrificial bonds presents a viable strategy for creating tough, versatile hydrogels.

Purpose of the Study:

• To synthesize poly(methacrylic acid) (PMA)/gelatin hydrogels crosslinked solely by physical bonds.
• To investigate the impact of gelatin addition on hydrogel structure and properties.
• To evaluate the mechanical performance, thermal stability, biocompatibility, and shape memory properties of the developed hydrogels.

Main Methods:

• Synthesis of PMA/gelatin hydrogels via thermally induced free-radical polymerization.
• Characterization of hydrogel structure, focusing on hydrophobic domain formation.
• Assessment of mechanical properties (tensile strength, toughness, compressive modulus, compressive strength), water content, thermal stability, fatigue resistance, biocompatibility, and shape memory effects.

Main Results:

• Gelatin addition promoted hydrophobic domains, acting as permanent crosslinking points without chemical crosslinkers.
• Increased PMA and gelatin content generally resulted in lower water content, enhanced thermal stability, and improved mechanical properties.
• Achieved tensile strength up to 1.44 MPa, toughness up to 4.91 MJ m⁻³, compressive modulus up to 0.75 MPa, and compressive strength up to 24.81 MPa with >50 wt.% water content.
• Demonstrated excellent fatigue resistance, biocompatibility, and shape memory properties.

Conclusions:

• PMA/gelatin hydrogels synthesized with physical crosslinking offer a promising alternative to chemically crosslinked systems.
• The developed hydrogels exhibit superior mechanical properties, comparable to super-strong hydrogels, making them suitable for demanding applications.
• Excellent biocompatibility and shape memory characteristics position these hydrogels as strong candidates for advanced biomedical and industrial uses.