Robust and Elastic Polymer Membranes with Tunable Properties for Gas Separation

Peng-Fei Cao*†, Bingrui Li†, Tao Hong§, Kunyue Xing§, Dmitry N. Voylov§, Shiwang Cheng†, Panchao Yin‡, Alexander Kisliuk†, Shannon M. Mahurin†, Alexei P. Sokolov†§, and Tomonori Saito*† 

† Chemical Sciences Division and ‡Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States

§ Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States

ACS Appl. Mater. Interfaces, 2017, 9 (31), pp 26483–26491

DOI: 10.1021/acsami.7b09017

Publication Date (Web): July 17, 2017

Copyright © 2017 American Chemical Society

*E-mail: caop@ornl.gov.; saitot@ornl.gov.

Polymer membranes with the capability to process a massive volume of gas are especially attractive for practical applications of gas separation. Although much effort has been devoted to develop novel polymer membranes with increased selectivity, the overall gas-separation performance and lifetime of membrane are still negatively affected by the weak mechanical performance, low plasticization resistance and poor physical aging tolerance. Recently, elastic polymer membranes with tunable mechanical properties have been attracting significant attentions due to their tremendous potential applications. Herein, we report a series of urethane-rich PDMS-based polymer networks (U-PDMS-NW) with improved mechanical performance for gas separation. The cross-link density of U-PDMS-NWs is tailored by varying the molecular weight (Mn) of PDMS. The U-PDMS-NWs show up to 400% elongation and tunable Young’s modulus (1.3-122.2 MPa), ultimate tensile strength (1.1-14.3 MPa), and toughness (0.7-24.9 MJ/m³). All of the U-PDMS-NWs exhibit salient gas-separation performance with excellent thermal resistance and aging tolerance, high gas permeability ( > 100 Barrer), and tunable gas selectivity (up to α[P_CO2/P_N2] ≈ 41 and α[P_CO2/P_CH4] ≈ 16). With well-controlled mechanical properties and gas-separation performance, these U-PDMS-NW can be used as a polymer-membrane platform not only for gas separation but also for other applications such as microfluidic channels and stretchable electronic devices.