Water scarcity is an urgent global problem, with increasing pressure every day from many factors such as climate change or increasing demand. The air we breathe usually contains high quantities of water vapour, which could be a potential alternative source of water, especially in isolated regions or regions affected by droughts. My researched aimed to synthesise metal-organic framework (MOF)-based hydrogels for atmospheric water harvesting. The purpose? Combining the strong water adsorption levels of the MOF MIL-101(Cr) with the temperature-responsive properties of a polymer hydrogel, PNIPAM.

MIL-101(Cr) is synthesised from a chromium precursor and terephthalic acid under hydrothermal conditions, where the chemicals are heated in an aqueous solution. The resulting MOF is then integrated into a polymer network with in-situ radical polymerisation, a process where the reactive molecules (the radicals) initiate the linking of smaller molecules into a polymer mesh, to form the MOF-hydrogel. Scanning electron microscopy (SEM) analyses the morphology of the MOF, hydrogel, and composite, while differential scanning calorimetry (DSC) analyses the thermal response of the material.

SEM findings showed the characteristic porous MOF structure alongside the polymer network, providing evidence of a successful formation of the MOF-hydrogel. DSC indicated a thermal transition around 32.2 °C, which is consistent with the temperature-responsive behaviour required for water release. These findings demonstrate the potential of combining MIL-101(Cr) with a responsive hydrogel to create a material for atmospheric water harvesting. Future work could analyse the composite's water uptake and release performance and determine its potential for energy-efficient water harvesting.