On the Thermocapillary Migration at the Liquid and Solid Aspects

Abstract

Thermocapillary migration is an interfacial phenomenon that describes liquid flow on a nonisothermal surface from warm to cold regions in the absence of external forces. It is a typical lubricant loss mechanism in tribosystems. To ensure continued reliability of lubricated assemblies, knowledge of the migration capacity of different liquids and solids is needed. In the present work, migration experiments were conducted on various liquid lubricants on different solid surfaces. It was found that polar lubricants such as ionic liquids and polyethylene glycol hardly migrate on the tested surfaces, and the antimigration capacity of the polytetrafluoroethylene surface was discovered to be very high. Particular attention is paid to the migration mechanism associated with surface tension and contact angle. General guidelines for evaluating the migration capacities of different liquids on solids are proposed.