Synthesis and Characterisation of new materials formed from metal-organic frameworks and glasses

Metal-organic frameworks (MOFs) are hybrid materials consisting of inorganic and organic building blocks which self-assemble into porous, three-dimensional structures. They are emerging as functional materials for gas storage and separation, catalysis and drug delivery. However, a drawback to their widespread application is that they are conventionally synthesised as microcrystalline powders. Heightened interest has been focused on a phenomenon exhibited by several MOFs: the ability to form a glass. The hybrid glasses derived from MOFs are markedly different from other glass categories such as organic, inorganic and metallic glasses. A significant proportion of MOF glasses are derived from zeolitic imidazolate frameworks (ZIFs). A ZIF that has exhibited remarkable glass forming ability is ZIF-62, [Zn(Im)1.75(bIm)0.25] where Im is imidazolate and bIm is benzimidazolate. Several studies have investigated composite formation with ZIF-62 as one of the components. Additionally, composites with glassy ZIF-62 (agZIF-62) have been fabricated. This thesis expands the scope of MOF glasses by exploring the formation of hybrid blends between agZIF-62 and an inorganic sodium phosphate glass. The concept of combining a MOF material with a phosphate glass is then extended to a prototypical crystalline ZIF, ZIF-8, [Zn(mIm)2], where mIm is 2-methylimidazolate, to improve the morphological constraints of the powdered ZIF. Further to this, an alternative methodology for combining MOFs and phosphate glasses is investigated, where ZIF-8 is grown in situ onto porous phosphate glass microspheres. In addition to combining MOFs with inorganic glasses, a comparative approach is taken to combine agZIF-62 with an organic polymer of intrinsic microporosity (PIM), PIM-1. The new materials synthesised by combining MOFs with either inorganic or polymeric glasses are extensively analysed using various techniques and their thermal and mechanical properties are assessed. In particular, focus is centred on identifying interfacial interactions between the two components of the synthesised materials using total scattering X-ray pair distribution function data, through the development of a new methodology. This work provides a basis into the realm of combining ZIF glasses with inorganic and polymeric glasses, with the aim of designing functionalised composites and blends exhibiting distinct properties from their parent materials. Moreover, it demonstrates how the coherent and continuous bulk morphologies of glasses of different types can be exploited.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2024

Author dc:creator

• Chester, Ashleigh

Advisors dc:contributor.advisor

• Bennett, Thomas Douglas
• Keen, David

• metal-organic framework
• inorganic glasses
• organic polymer glasses
• composites
• blends
• pair distribution function analysis
• interfacial analysis

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/5f2facbe-ac4c-4847-9ec2-e5c2def2605e/download
• https://creativecommons.org/licenses/by/4.0/

Language dc:language

eng

Author Identifier

0000-0003-4605-6651

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/377425