Phosphonic acid derivatives are used for surface modification on oxidized metals such as Al2O31), TiO22), ZrO23), SiO24), Mica5), stainless(SS316L) 6), nitinol7), hydroxyapatite8), AgO9), ZnO10), ITO11,12).
For a long time, organosilanes have been used to form self assembled monolayer (SAM) on the metal oxide. However, it is not always adaptable in the applications due to the poor stability and polymerization of the reagent with each other. On the other hand, phosphonic acid derivatives equally form a SAM on the metal oxide despite being very stable compounds. Also, phosphonic acid derivatives have been reported to use formation of more stable and dense SAM than organosilanes. Klauk et. al. and Sekitani et. al. show alkyl phosphonate SAM on Al2O3 is more useful than the trichlorosilane derivatives SAM as an conductor film of an organic transistor13).
11-HUPA is an alkyl phosphonic acid derivative containing hydroxyl termination. Pulsipher et. al. prepare two different patterns of surfaces (aldehyde and carboxylic acid) by controlling oxidizing condition on the ITO substrate modified with 11-HUPA12).