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Tuning Selectivities in Gas Separation Membranes Based on Polymer-Grafted Nanoparticles
Connor R Bilchak1, Mayank Jhalaria1, Yucheng Huang2
1Department of Chemical Engineering, Columbia University, New York, New York 10027, United States.
ACS Nano
|November 20, 2020
Summary
Adding free polymer chains to polymer-grafted nanoparticle (GNP) membranes significantly enhances gas selectivity. This manipulation of free volume distribution offers a new pathway for advanced gas separation technologies.
Area of Science:
- Materials Science
- Chemical Engineering
- Nanotechnology
Background:
- Polymer membranes are essential for gas mixture separations in sustainability applications.
- Existing polymer-grafted nanoparticle (GNP) membranes offer improved permeability but limited selectivity.
- There is a need to enhance selectivity and mechanical properties of membranes for gas separations.
Purpose of the Study:
- To investigate the effect of adding free polymer chains to GNP membranes.
- To understand how free volume distribution influences gas transport properties.
- To establish a method for favorably manipulating the selective gas transport in GNP membranes.
Main Methods:
- Fabrication of polymer-grafted nanoparticle (GNP) membranes with varying amounts of added free polymer.
- Characterization of membrane structure and free volume distribution.
- Measurement of gas permeability and selectivity for different gas mixtures.
Main Results:
- GNP membranes exhibit spatially heterogeneous transport due to free volume distribution.
- Addition of free polymer chains can increase gas selectivity by up to two orders of magnitude.
- Free chains comparable in length to grafts preferentially hinder larger gas transport, significantly boosting selectivity.
Conclusions:
- Free polymer chains can be used to favorably manipulate the selective gas transport properties of GNP membranes.
- The entropic effects associated with free chain addition are key to enhancing selectivity.
- This approach offers a promising strategy for developing high-performance membranes for gas separations.
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