Mixed-Matrix Membranes Integrating Metal-Organic Frameworks: Thermo-Mechanical Properties and Engineering Performance

Polymer composite membranes containing nanostructured fillers have many potential applications in industrial sectors. For example, in emergent technologies ranging from carbon dioxide capture and sequestration to hydrogen purification, and for use in water desalination and vapor recovery systems, as well as in medical devices and smart sensors. Next-generation mixed-matrix membranes (MMMs) which incorporate porous metal-organic frameworks (MOFs), offer the unique opportunity for combining high selectivity and chemical tuneability of MOFs with the ease of processing and robustness intrinsic to conventional polymers. While the development of such MOF-polymer mixed-matrix membranes is in its infancy, there are already archetypal composite systems recently discovered that demonstrate substantial improvement in its functional performance (particularly gas/liquid permeability and selectivity properties). Much progress has been accomplished in this rapidly growing area. However, many important questions remain to be answered about its core mechanical-thermal properties and long-term chemical stability; its structure-function mechanical correlation information is scarce and, hitherto membrane structural integrity (under static or dynamic loading) is not well understood. This project will address the aforementioned problems, establishing an accurate knowledge of the underpinning physical properties, and pinpointing microscopic mechanisms that control the structural and functional performance of novel membranes. This research will yield systematic structure-function relationships, formulate innovative methodologies and detailed material model descriptions, which will enable prediction, rational design and engineering of new membranes. Resilient composite membranes featuring an improved damage tolerance coupled with optimal functionalities will enable many energy, environmental and multifunctional technologies benefitting the wider public.

Beneficiaries:
(1) Commercial firms developing, manufacturing, and deploying membrane materials for energy-efficient applications. There are many such companies in the UK, including SMEs designing, fabricating and deploying polymer-based membranes for commercial processes, e.g. hydrogen separation, waste water treatment, desalination and filtrations. Moreover, the research output may benefit UK firms manufacturing value-added applications, particularly for pharmaceutical uses and medical devices.

(2) Organisations with an interest in characterisation of novel materials, polymer-based nanocomposites and multifunctional films. The two project partners (NPL and Anton Parr) are example organisations who recognised the importance in development of new characterisation methodologies and establishment of standards for extracting quantitative mechanical-thermal property information (see Letter of Supports).

(3) UK firms and organisations interested in development and implementation of next-generation membranes for CO2 separations. This will encompass, either for natural gas purification (CO2/CH4 separation), or for challenging environmental remediation usage in terms of post-combustion CO2 capture from flue gases. The scientific understanding and material data established in this programme could benefit not only engineers who are developing improved carbon capture technologies, but also important to policy makers for pinpointing promising research of societal and economic impact.

(4) Firms and industries involved in membrane-oriented vapour recovery systems and chemical processes, which are fast gaining a foothold in the steadily growing world membrane market. Of particular relevance is utilisation of efficient membrane-based technology for dehydration of organic solvents (e.g. ethanol, butanol, pentanol), and for hydrocarbon recovery systems (e.g. ethylene/nitrogen separations). New information about material stability and resilience, damage tolerance data of membranes will accelerate development of emergent technologies.

Dissemination:
The PI has extensive experience of publishing in leading journals. For greatest visibility and dissemination, the outcome of this project will be published in high-impact multidisciplinary journals. A project website will be set up for effective distribution of information, enabling dissemination of technical innovations to the broadest possible audience triggering follow-on studies. Key results will be presented at reputable international conferences (e.g. MOF2016). Close contacts will be fostered with UK and international researchers in the field building new links via conferences and workshops.

Impacts:
The proposed programme will establish a new area of research addressing both the scientific and technological challenges, underwriting the engineering performance and long-term durability of next-generation membranes. The project is timely, and will yield major contributions not only on novel materials property data, but also new insights into mechanisms controlling the thermo-mechanical stability of nanocomposites containing metal-organic frameworks (MOFs) as fillers. Users of materials property information comprise many UK SMEs and industries involved in production and deployment of membranes for gas separations, water purification and electrochemical technologies, bringing substantial economic benefits to the UK. Membranes with an optimal combination of structural damage tolerance and separation performance will increase practical viability of post-combustion CO2 capture from flue gases, central to advancement of environmental remediation solutions. Innovative procedures for characterising complex materials and for extracting dynamic properties will benefit project partners, and commercial organisations whose marketing strategy is to widen usage and standardisation of cutting-edge materials characterisation techniques. These outcomes could materialise in short to medium term.