Ultrathin Polyamide Nanofilms with Controlled Microporosity for Enhanced Solvent Permeation

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Technology

Background:

• Organic solvent nanofiltration (OSN) is crucial for low-carbon separation applications, offering significant energy savings.
• Developing polyamide nanofilms with controlled structures is key for OSN efficiency but presents technical challenges.
• Existing methods often face limitations in controlling film thickness and porosity.

Purpose of the Study:

• To synthesize ultrathin polyamide nanofilms with precisely controlled microporosity and morphology for enhanced OSN.
• To overcome the limitations of interfacial polymerization by employing a homogenous organic phase synthesis.
• To demonstrate a novel approach for fabricating high-performance OSN membranes.

Main Methods:

• Utilized molecular layer deposition for synthesizing ultrathin polyamide nanofilms.
• Employed nonplanar and rigid amine monomers to enhance microporosity.
• Controlled nanofilm thickness linearly at the nanometer scale.
• Conducted OSN experiments using ethanol and methanol.

Main Results:

• Achieved ultrathin polyamide nanofilms with controlled microporosity and morphology.
• Demonstrated superior OSN performance compared to existing membranes.
• Obtained high ethanol and methanol permeances (5.5 and 14.6 L m⁻² h⁻¹ bar⁻¹, respectively) with a low molecular weight cutoff of 300 Da.
• Exhibited stable separation performance over long-term operation.

Conclusions:

• The molecular layer deposition method provides precise control over polyamide nanofilm structure for OSN.
• This approach enables the fabrication of high-performance membranes with tunable separation characteristics.
• The developed OSN membranes offer a promising alternative for efficient and low-carbon separation processes.