PREVENTION OF LIQUID SPREADING OF CREEPING
Abstract
The spreading of liquids over solid surfaces can be prevented by three different approaches: (a) the liquid may be inherently nonspreading in its pure state, (b) the liquid can be made nonspreading by the addition of carefully selected solutes, or (c) the solid surface can be modified by coating it with substances of low surface energy. The present-day requirements for nonspreading oils for watches, fuses, and various types of indicating instruments are very stringent. Methods for fulfilling these requirements were examined in terms of the basic mechanism of spreading and wetting, the effect of chemical composition on spreading, and the use of oleophobic additives. The difficulties in obtaining appropriate liquids can be avoided by the alternative approach of modifying the solid surface. Monolayer coatings of some selected substances, although effective in the prevention of oil spreading, are sometimes too readily removed. Coatings of some fluorinated polymers however are easy to apply and remain effective when laid down in the form of a circular ring surrounding the oil drop. Thus, it becomes possible to employ any one of the many available spreading-type lubricating oils. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1963
- Accession Number
- AD0413665
Entities
People
- Marianne K. Bernett
- William A. Zisman
Organizations
- United States Naval Research Laboratory