Structural Characterization of Ordered Mesoporous Silica Prepared by a Sol-Gel Process Using Urea-Based Cationic...

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Mesoporous silica nanoparticles (MSNs) are crucial for catalysis, drug delivery, and adsorption.
• Controlling MSN morphology and pore structure is key to optimizing their performance.
• Gemini surfactants offer tunable properties for templating MSN synthesis.

Purpose of the Study:

• To investigate the impact of gemini surfactant spacer length on mesoporous silica nanoparticle synthesis.
• To characterize the resulting nanoparticle morphology and pore structure.
• To understand the relationship between surfactant structure and MSN properties.

Main Methods:

• Sol-gel synthesis under basic conditions.
• Utilized gemini surfactants with urea headgroups and varying spacer lengths.
• Characterization via nitrogen porosimetry, SAXS, USANS, SEM, and TEM.

Main Results:

• Spherical and cylindrical nanoparticles were formed in varying proportions based on spacer length.
• Most materials exhibited the hexagonal pore structure of MCM-41 molecular sieves.
• SAXS and TEM revealed the influence of spacer length on lattice parameter and domain size.

Conclusions:

• Gemini surfactant spacer length significantly affects MSN morphology and pore network parameters.
• The shortest spacer length resulted in a deviation from the characteristic MCM-41 structure.
• No direct correlation was found between micelle shape/size and pore size, indicating broad applicability of these surfactants for MCM-41 synthesis.