Aerogels and polymorphism of isotactic poly(4-methyl-pentene-1)

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Aerogels offer unique porous structures with tunable properties.
• Isotactic poly(4-methyl-pentene-1) (i-P4MP1) is a semicrystalline polymer with potential for aerogel fabrication.
• Controlling the crystalline phases of polymers is crucial for tailoring aerogel characteristics.

Purpose of the Study:

• To prepare monolithic and highly crystalline aerogels of i-P4MP1.
• To investigate the influence of different solvents on the crystalline phases and resulting aerogel structure.
• To assess the suitability of these aerogels for porous membrane applications.

Main Methods:

• Preparation of thermoreversible i-P4MP1 gels.
• Sudden solvent extraction using supercritical carbon dioxide (scCO2).
• Characterization of crystalline phases (e.g., Form I, II, III, IV) and cocrystalline phases.
• Analysis of aerogel morphology and pore structure using scanning electron microscopy (SEM) and N2 sorption.

Main Results:

• Monolithic and highly crystalline i-P4MP1 aerogels were successfully synthesized.
• The choice of solvent dictated the crystalline phase (Form I or II) of the resulting aerogels.
• Aerogels derived from Form I gels exhibited superior structural stability due to the absence of phase transitions during scCO2 extraction.
• All aerogels displayed interconnected macroporous and mesoporous structures with a wide size distribution and minimal micropores.

Conclusions:

• Solvent selection is a critical parameter in controlling the crystalline structure and stability of i-P4MP1 aerogels.
• Aerogels formed from Form I crystalline phases are promising for developing robust porous membranes.
• The developed aerogels possess desirable porous architectures for various advanced material applications.