Optical Analysis of the Internal Void Structure in Polymer Membranes for Gas Separation
Global warming by greenhouse gas emissions is one of the main threats of our modern society, and efficient CO<sub>2</sub> capture processes are needed to solve this problem. Membrane separation processes have been identified among the most promising technologies for CO<sub>2</su...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-11-01
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| Series: | Membranes |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-0375/10/11/328 |
| _version_ | 1797548772385882112 |
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| author | Chiara Muzzi Alessio Fuoco Marcello Monteleone Elisa Esposito Johannes C. Jansen Elena Tocci |
| author_facet | Chiara Muzzi Alessio Fuoco Marcello Monteleone Elisa Esposito Johannes C. Jansen Elena Tocci |
| author_sort | Chiara Muzzi |
| collection | DOAJ |
| description | Global warming by greenhouse gas emissions is one of the main threats of our modern society, and efficient CO<sub>2</sub> capture processes are needed to solve this problem. Membrane separation processes have been identified among the most promising technologies for CO<sub>2</sub> capture, and these require the development of highly efficient membrane materials which, in turn, requires detailed understanding of their operation mechanism. In the last decades, molecular modeling studies have become an extremely powerful tool to understand and anticipate the gas transport properties of polymeric membranes. This work presents a study on the correlation of the structural features of different membrane materials, analyzed by means of molecular dynamics simulation, and their gas diffusivity/selectivity. We propose a simplified method to determine the void size distribution via an automatic image recognition tool, along with a consolidated Connolly probe sensing of space, without the need of demanding computational procedures. Based on a picture of the void shape and width, automatic image recognition tests the dimensions of the void elements, reducing them to ellipses. Comparison of the minor axis of the obtained ellipses with the diameters of the gases yields a qualitative estimation of non-accessible paths in the geometrical arrangement of polymeric chains. A second tool, the Connolly probe sensing of space, gives more details on the complexity of voids. The combination of the two proposed tools can be used for a qualitative and rapid screening of material models and for an estimation of the trend in their diffusivity selectivity. The main differences in the structural features of three different classes of polymers are investigated in this work (glassy polymers, superglassy perfluoropolymers and high free volume polymers of intrinsic microporosity), and the results show how the proposed computationally less demanding analysis can be linked with their selectivities. |
| first_indexed | 2024-03-10T15:05:28Z |
| format | Article |
| id | doaj.art-c9592c0ca45a44cc9f74770101ac3e7d |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-10T15:05:28Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-c9592c0ca45a44cc9f74770101ac3e7d2023-11-20T19:52:04ZengMDPI AGMembranes2077-03752020-11-01101132810.3390/membranes10110328Optical Analysis of the Internal Void Structure in Polymer Membranes for Gas SeparationChiara Muzzi0Alessio Fuoco1Marcello Monteleone2Elisa Esposito3Johannes C. Jansen4Elena Tocci5Institute on Membrane Technology (CNR-ITM), Via P. Bucci, 17/C, 87036 Rende, ItalyInstitute on Membrane Technology (CNR-ITM), Via P. Bucci, 17/C, 87036 Rende, ItalyInstitute on Membrane Technology (CNR-ITM), Via P. Bucci, 17/C, 87036 Rende, ItalyInstitute on Membrane Technology (CNR-ITM), Via P. Bucci, 17/C, 87036 Rende, ItalyInstitute on Membrane Technology (CNR-ITM), Via P. Bucci, 17/C, 87036 Rende, ItalyInstitute on Membrane Technology (CNR-ITM), Via P. Bucci, 17/C, 87036 Rende, ItalyGlobal warming by greenhouse gas emissions is one of the main threats of our modern society, and efficient CO<sub>2</sub> capture processes are needed to solve this problem. Membrane separation processes have been identified among the most promising technologies for CO<sub>2</sub> capture, and these require the development of highly efficient membrane materials which, in turn, requires detailed understanding of their operation mechanism. In the last decades, molecular modeling studies have become an extremely powerful tool to understand and anticipate the gas transport properties of polymeric membranes. This work presents a study on the correlation of the structural features of different membrane materials, analyzed by means of molecular dynamics simulation, and their gas diffusivity/selectivity. We propose a simplified method to determine the void size distribution via an automatic image recognition tool, along with a consolidated Connolly probe sensing of space, without the need of demanding computational procedures. Based on a picture of the void shape and width, automatic image recognition tests the dimensions of the void elements, reducing them to ellipses. Comparison of the minor axis of the obtained ellipses with the diameters of the gases yields a qualitative estimation of non-accessible paths in the geometrical arrangement of polymeric chains. A second tool, the Connolly probe sensing of space, gives more details on the complexity of voids. The combination of the two proposed tools can be used for a qualitative and rapid screening of material models and for an estimation of the trend in their diffusivity selectivity. The main differences in the structural features of three different classes of polymers are investigated in this work (glassy polymers, superglassy perfluoropolymers and high free volume polymers of intrinsic microporosity), and the results show how the proposed computationally less demanding analysis can be linked with their selectivities.https://www.mdpi.com/2077-0375/10/11/328molecular dynamicssimulationfree volume element size distributionnon-accessible regionsselectivityglassy polymers |
| spellingShingle | Chiara Muzzi Alessio Fuoco Marcello Monteleone Elisa Esposito Johannes C. Jansen Elena Tocci Optical Analysis of the Internal Void Structure in Polymer Membranes for Gas Separation Membranes molecular dynamics simulation free volume element size distribution non-accessible regions selectivity glassy polymers |
| title | Optical Analysis of the Internal Void Structure in Polymer Membranes for Gas Separation |
| title_full | Optical Analysis of the Internal Void Structure in Polymer Membranes for Gas Separation |
| title_fullStr | Optical Analysis of the Internal Void Structure in Polymer Membranes for Gas Separation |
| title_full_unstemmed | Optical Analysis of the Internal Void Structure in Polymer Membranes for Gas Separation |
| title_short | Optical Analysis of the Internal Void Structure in Polymer Membranes for Gas Separation |
| title_sort | optical analysis of the internal void structure in polymer membranes for gas separation |
| topic | molecular dynamics simulation free volume element size distribution non-accessible regions selectivity glassy polymers |
| url | https://www.mdpi.com/2077-0375/10/11/328 |
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