We used our physical chemistry knowledge that a surfactant's behaviour is primarily governed by its head group and chain length . As highlighted in Figure for an example surfactant (Texapon ® SB 3 KC), we can enumerate all the distinct functional groups (FG) -either algorithmically , or by hand since we only have twelve surfactants here -and count their frequency. This data is summarised in the SI of our formulations dataset . Additionally, not highlighted in Figure , is the length of the alkyl chain, (CH2)x. As we worked with real, industrial materials, these surfactant ingredients have a distribution of chain lengths which we characterised via UPLC-MS, as detailed in the SI of our previous work . This FG and chain length data is represented by the orange matrix in the top-right hand corner of Figure . This shows that we can take the matrix dot product of the experimental surfactant concentrations and FG data to re-express the surfactants in terms of concentrations of functional groups and append the polymer and thickener concentrations to generate a suitable featurisation for a sub-system of formulation samples. (" !"#$%! , " !&'( )