Measuring acidity at phase interfaces

pH is the most widely used acidity measure but can currently be reliably measured only in bulk solution, as opposed to phase interfaces and surfaces. This project will revolutionise pH measurement by developing experimental approach for rigorous pH measurements at phase interfaces. The approach will combine the novel unified pH (pHabs) concept with a set of specially designed pairs of fluorescent ratiometric pH-sensitive molecular probes (one hydrophobic and the other hydrophilic). Rigorous and accessible quantification of pHabs on a variety of interfaces will become possible. This leads to a better understanding and control of various interfacial processes, which are influenced by pH and are crucial in real-world applications. The developed approach will be applied to exemplary applications from different domains of science to demonstrate its usefulness across disciplines: atmospheric aerosol, electrospray ionization and “on-water” acid catalysis.