Acemannan Gels and Aerogels

Area of Science:

• Materials Science
• Biomaterials Engineering
• Chemical Engineering

Background:

• Acemannan (AC), a polysaccharide, possesses valuable bioactive properties.
• Developing novel AC-based materials like gels and aerogels is crucial for expanding its applications.
• Controlling the chemical structure and physical properties of AC materials is key for tailored functionalities.

Purpose of the Study:

• To synthesize two types of acemannan (AC) physical gels and their corresponding aerogels.
• To investigate the impact of different gelation methods (alkali vs. non-solvent diffusion) on AC's chemical structure.
• To characterize the physical properties (porosity, surface area) of the resulting AC aerogels.

Main Methods:

• Gelation of AC induced by alkali or non-solvent diffusion.
• Supercritical CO₂ drying to convert physical gels into aerogels.
• Fourier-transform infrared spectroscopy (FTIR) for chemical structure analysis.
• Porosimetry and surface area analysis for material characterization.

Main Results:

• Two distinct AC physical gels and aerogels were successfully produced.
• Alkali diffusion led to significant AC deacetylation, altering its chemical structure.
• Non-solvent treatment maintained the native chemical structure of AC.
• Both AC aerogels exhibited mesoporous nanostructures with high specific surface areas (>370 m²/g) and pore sizes up to 6.4 nm.
• Syneresis was observed in gels, and volume reduction occurred during drying.

Conclusions:

• The choice of gelation method critically influences the chemical integrity of acemannan.
• Supercritical CO₂ drying effectively produces mesoporous AC aerogels with high surface areas.
• These AC physical gels and aerogels offer promising platforms for applications leveraging AC's bioactivity and material properties.