In this thesis, we investigated the formation process of self-assembled monolayers (SAMs) of organophosphonic acids on ZnO surfaces. There was the effect of solvent on the coverage of ODPA SAM on zinc oxide surface. The coverage for isopropanol was 75% and that of ethanol was 97%. In addition to solvent type, the coverage was also affected by concentration and solution temperature. Both high concentration/ high solution temperatures (600 ) produced high coverage in a short immersion time. In addition to contact angle measurement, the ODPA SAMs were characterized using FTIR. The FTIR result of the ODPA SAMs indicates the formation of ordered monolayers. When ODPA SAMs were exposed to water, the contact angle decreased from 126 to 74 in 36 hrs. The ODPA SAMs were also exposed to UV ozone cleaner. The contact angle decreased as exposure time increased. The rate of degradation of the ODPA SAM when exposed to UV ozone was much higher than when exposed to water. Keywords: self-assembly monolayers (SAMs), octadecylphosphonic acid (ODPA), zinc oxide (ZnO) thin films, characterization