Thermosensitive Shape-Memory Poly(stearyl acrylate-co-methoxy poly(ethylene glycol) acrylate) Hydrogels

Area of Science:

• Polymer Science
• Biomaterials Engineering
• Materials Science

Background:

• Stimuli-sensitive hydrogels are crucial for developing intelligent biomaterials.
• Existing hydrogels often lack specific functionalities like shape memory.
• Thermosensitive materials offer tunable properties for advanced applications.

Purpose of the Study:

• To synthesize and characterize a novel thermosensitive hydrogel with shape-memory capabilities.
• To investigate the influence of hydrophobic and hydrophilic components on hydrogel properties.
• To evaluate the potential of the developed hydrogel for biomaterial applications.

Main Methods:

• Copolymerization of stearyl acrylate (SA) and methoxy poly(ethylene glycol) acrylate (MPGA) to form poly(SA-co-MPGA) gels.
• Differential scanning calorimetry (DSC) and compression tests to analyze thermal and mechanical properties at varying temperatures.
• Swelling studies in water at 50 °C to assess volume stability and deformation behavior.

Main Results:

• Poly(SA-co-MPGA) hydrogels with a stearyl acrylate mole fraction (xSA) greater than 0.5 exhibited a crystalline-to-amorphous transition around 40 °C.
• This transition resulted in a reversible hard-to-soft behavior based on stearyl side chain crystallization.
• The hydrogels demonstrated shape-memory function, being soft and deformable at 50 °C and stiffening reversibly upon cooling.

Conclusions:

• A novel thermosensitive poly(SA-co-MPGA) hydrogel with shape-memory properties was successfully developed.
• The hydrogel's reversible hard-to-soft transition is attributed to the temperature-dependent crystalline structure of stearyl side chains.
• The incorporation of biocompatible poly(ethylene glycol) in MPGA suggests potential for intelligent biomaterial applications.