Synthesis And Surface Wettability Of TiO₂/CuO Nanocomposites

In this paper,we describe the preparation of CuO nanocrystals with different morphology by solvothermal method and the study of wettability of the as-prepared films.Moreover,we also describe the preparation of TiO₂/CuO nanocomposites by one step and two step solvothermal methods and the study of wettability of the as-prepared TiO₂/CuO nanocomposites films.The main study is summarized as follows:CuO nanocrystals with different morphology have been prepared by solvothermal method using Cu?NO3?2·3H2O as chemical precursor.The influence of reaction conditions,including Cu?NO3?2 concentration,reaction time,reaction temperature and the molar ratio of Cu?NO3?2/NH3·H2O,on the morphological evolution and surface wettability of CuO has been characterized by XRD,FTIR,SEM and contact angle measurement.The results indicated that by controlling the Cu?NO3?2 concentration,CuO nanocrystals with different morphology composed of nanoparticles,nanoshuttles and nanoflowers were prepared;by adjusting reaction time,Cu2?OH?3NO3 nanowires,Cu2?OH?3NO3 nanoshuttles,CuO nanoflowers were prepared;by controlling reaction temperature,Cu2?OH?3NO3 nanoshuttles,Cu?OH?2 nanoflower,CuO nanoflower can be obtained;by modifing the molar ratio of Cu?NO3?2/NH3·H2O,Cu2?OH?3NO3 nanoshuttles,CuO nanoflower,CuO nanoparticle aggregates and CuO urchin like microspheres were obtained.It was found that among these different shaped CuO nanocrystals,nanoflower-like CuO film with hierarchical structure was superhydrophilic with a water CA of 1.7°,and exhibited excellent water repellency with a water CA of 164.4° after surface fluorination.TiO₂/CuO nanocomposites were prepared by one-step and two-step solvothermal method,respectively.The results indicated that at low TiO₂ content,nanoflower-like TiO₂/CuO composites have been synthesized by both one-step and two-step solvothermal method.Nanoflower-like TiO₂/CuO composites were prepared from the intermediate of TiO₂·Cu2?OH?3NO3 and then TiO₂·Cu?OH?2 in one-step solvothermal method whereas nanoflower-like TiO₂/CuO composites were prepared by depositing TiO₂ particles on the surface of CuO nanoflower in two-step solvothermal method.With increasing TiO₂ content,the structure of nanoflower-like will be destroyed due to the change of growth mechanisms in one-step solvothermal method and the interior space of CuO nanoflower filling with TiO₂ particles in two-step solvothermal method.Compared with the TiO₂? films synthesized under the same content,the hydrophilic and hydrophobic properties increase of TiO₂/CuO ? composite films decreased obviously with the increase of TiO₂ content.The hydrophilic and hydrophobic properties of TiO₂/CuOII film gradually weakened with the increase of TiO₂ content.Compared with the TiO₂ II films synthesized under the same content,the hydrophilic and hydrophobic properties increase of TiO₂/CuOII composite films showed the same trend as TiO₂/CuO ? composite films,due to the decrease of surface roughness.