Surface forces apparatus

A current Surface Force Apparatus. The model shown is the SFA 2000.[1]

The Surface Force Apparatus (SFA) is a scientific instrument which measures the interaction force of two surfaces as they are brought together and retracted using multiple beam interferometry to monitor surface separation and directly measure contact area and observe any surface deformations occurring in the contact zone. One surface is held by a cantilevered spring, and the deflection of the spring is used to calculate the force being exerted.[2] The technique was pioneered by David Tabor and R.H.S. Winterton in the late 1960s at Cambridge University.[3] By the mid-1970s, J.N. Israelachvili had adapted the original design to operate in liquids, notably aqueous solutions, while at the Australian National University,[4] and further advanced the technique to support friction and electro-chemical surface studies[5] while at the University of California Santa Barbara.

  1. ^ "Home - SurForce LLC". SurForce LLC. Retrieved 2018-10-26.
  2. ^ Israelachvili, J; Min, Y; Akbulut, M; Alig, A; Carver, G; Greene, W; Kristiansen, K; Meyer, E; Pesika, N; Rosenberg, K; Zeng, H (2010). "Recent advances in the surface forces apparatus (SFA) technique". Reports on Progress in Physics. 73 (3): 036601. Bibcode:2010RPPh...73c6601I. doi:10.1088/0034-4885/73/3/036601. ISSN 0034-4885. S2CID 53958134.
  3. ^ Tabor, D.; Winterton, R. H. S. (30 September 1969). "The Direct Measurement of Normal and Retarded van der Waals Forces". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 312 (1511): 435–450. Bibcode:1969RSPSA.312..435T. doi:10.1098/rspa.1969.0169. S2CID 96200833.
  4. ^ Israelachvili, J. N.; Adams, G. E. (26 August 1976). "Direct measurement of long range forces between two mica surfaces in aqueous KNO3 solutions". Nature. 262 (5571): 774–776. Bibcode:1976Natur.262..774I. doi:10.1038/262774a0. S2CID 4170776.
  5. ^ Israelachvili, J; Min, Y; Akbulut, M; Alig, A; Carver, G; Greene, W; Kristiansen, K; Meyer, E; Pesika, N (2010-01-27). "Recent advances in the surface forces apparatus (SFA) technique". Reports on Progress in Physics. 73 (3): 036601. Bibcode:2010RPPh...73c6601I. doi:10.1088/0034-4885/73/3/036601. ISSN 0034-4885. S2CID 53958134.