Temperature Effects of Water-Metallic Interface Energies and Their Influence on Contact Angle Test for Surface Cleanliness: A Combined Experimental and Molecular Simulation Study

Abstract To ensure the effectiveness of the high-power-laser facilities, the cleanliness of metal parts is of significance. In this paper, molecular modelings combined with contact angle tests were performed, in order to investigate the temperature effects of water-metallic interface energies and their influence on the tests for surface cleanliness. As results, the attractive forces were found between water and metallic surfaces, in which van der Waals forces contribute most, and the energies raised with elevated temperatures from 291 K to 303 K; meanwhile, the contact angle tests show both the Al and Fe components are hydrophilic, and the contact angle reduced with elevated temperatures; furthermore, correlations can be found between the energy change and the contact angle at varying temperatures. These conclusions are helpful in the accurate testing of surface cleanliness for optical scientific facilities.