In recent work with Unilever we have been investigating the structure of gels formed by partially oxidised cellulose nanofibrils for use in sustainable personal care products. These studies find strong gelation in the presence of anionic surfactants, but nonionic surfactants gel the suspensions of nanofibrils only in the presence of salts. Here we propose to compare the adsorption of anionic and nonionic surfactants on films prepared from the partially oxidised cellulose nanofibrils in the presence and absence of monovalent and divalent cations at concentrations relevant to gel formation. This will help us to determine the role of micelle binding to the cellulose in the formation of gels in this system. This is a resubmission of RB1210093 with new data demonstrating our ability to make sufficiently smooth films for reflectivity studies.