Coatings for Atomically Thin Membrane Selectivity

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Solution Overview

Problem

Membranes used in filtration applications, particularly those made from atomically thin materials, face challenges due to intrinsic and extrinsic defects that lead to leakage and decreased selectivity, as these defects allow free transport of ions, solutes, and gases, compromising their performance in separation processes.

Innovation Solution

A method involving the application of a coating on opposite sides of an atomically thin active layer to affect the through-size of channels, using materials like polymers, gels, or colloids to interact through channels, thereby reducing non-selective leakage pathways and enhancing selectivity without significantly impacting water permeance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If atomically thin membranes are used to increase flux, then water permeance is improved, but selectivity deteriorates due to defects causing leakage

Engineering Contradiction:

Improvewater fluxVSAvoidselectivity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces coating materials (polymers, colloids, or small molecules) as intermediary substances that bridge the defect regions in atomically thin membranes. These coating materials selectively interact with and seal the defective channels while preserving the integrity of functional channels, thereby mediating between the high flux capability of thin membranes and the need for selectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies coating materials selectively to defect regions rather than uniformly across the entire membrane surface. By targeting only the defective channels that cause non-selective leakage, the coating modifies the local properties of problematic areas while leaving the functional channels unchanged, thus maintaining high water flux while improving selectivity.

Inventive Principle:

Principle #3Local quality

2Reliability

If coating materials are applied to seal defects, then selectivity is improved, but channel through-size may be reduced

Engineering Contradiction:

ImproveselectivityVSAvoidchannel through-size

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent applies coating materials in controlled amounts that are sufficient to seal defective channels but not excessive enough to block functional channels. By carefully controlling the coating thickness and material deposition, the patent achieves partial action that targets only the necessary defect regions without over-treating the membrane structure.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent modifies the physical and chemical parameters of the coating materials (such as molecular size, charge, and hydrophobicity) to ensure they selectively interact with defect regions. By adjusting these parameters, the coating materials can effectively seal defects while maintaining appropriate channel through-sizes for functional channels.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12083483B2Coatings to improve the selectivity of atomically thin membranes

Publication Date: 2024.09.10 MASSACHUSETTS INST OF TECH

AI summary

Disclosed embodiments are related to mitigating leaks in membranes and/or improving the selectivity of membranes.