Preparation of Flower-like ZnO Micro-sphere Powders and Their Surface Wettability Modification

摘要

Three-dimensitional flower-like ZnO powders were prepared by using a simple aqueous solution method.Their surface wettability was modified via some long chain alkylsilanes with low surface energy.The microstructures and the wettability properties were studied by scanning electron microscopy (SEM),X-ray diffractometer (XRD) and contact angle measurement (CAM).The ZnO powders are spheric and are about 5 micrometers in diameter.The boundary of the microspheres are not smooth,but petaliform in nano-scale,which demonstrate a hierarchical microstructure.The as-synthesized powders have a superhydrophobicity with water contact angle of more than 150°,and have a high adhesion to water.After modified by alkylsilanes,however,the ZnO powders demonstrate a strong anti-adhesion to water.When modified by fluorinated alkylsilanes,the surface of ZnO microspheres had a water contact angle up to 170°.Also,the water droplet could bounce against the surface just like a spring ball,and there are not any water traces left when the water droplets contact the surfaces of ZnO powders.The results provide a simple method to repel the water wetting and will be helpful to disperse the powders especially in a humid environment.