Design Ultrathin Polyamide Membranes against Funnel Effect: A Novel Zone-of-Influence-Based Approach

Area of Science:

• Materials Science
• Chemical Engineering
• Membrane Science

Background:

• Ultrathin polyamide membranes offer high water permeance but are limited by substrate-induced funnel effects.
• Current methods for optimizing substrate porosity rely on time-consuming trial-and-error, yielding limited design insights.

Purpose of the Study:

• To introduce a novel zone-of-influence (ZOI)-based approach for intuitive and efficient design of ultrathin membranes.
• To analyze the impact of substrate pore size and film thickness on membrane water permeance.
• To establish a fundamental structure-performance relationship for membrane optimization.

Main Methods:

• Numerical simulations to analyze funnel effects in thin and thick polyamide films.
• Development of the zone-of-influence (ZOI) concept based on water permeation efficiency.
• Analytical modeling using the superposition principle to correlate membrane structure with performance.

Main Results:

• Thin films (aspect ratio θ ≤ 0.5) exhibit more severe funnel effects than thick films (θ ≫ 1).
• A linear relationship was identified between ZOI and the aspect ratio (θ).
• An analytical model reveals the structure-performance relationship involving aspect ratio and substrate porosity.

Conclusions:

• The ZOI-based approach offers an intuitive and efficient method for designing ultrathin membranes, surpassing traditional trial-and-error.
• This study provides essential design tools and fundamental insights for advancing high-performance membrane technology.
• Optimizing membrane structure through ZOI analysis facilitates achieving target water permeance effectively.