Forces between mica surfaces, prepared in different ways, across aqueous and nonaqueous liquids confined to molecularly thin films

Susan Perkin; Liraz Chai; Nir Kampf; Uri Raviv; Wuge Briscoe; Iain Dunlop; Simon Titmuss; Minseok Seo; Eugenia Kumacheva; Jacob Klein

doi:10.1021/la053097h

Forces between mica surfaces, prepared in different ways, across aqueous and nonaqueous liquids confined to molecularly thin films

Langmuir. 2006 Jul 4;22(14):6142-52. doi: 10.1021/la053097h.

Authors

Susan Perkin¹, Liraz Chai, Nir Kampf, Uri Raviv, Wuge Briscoe, Iain Dunlop, Simon Titmuss, Minseok Seo, Eugenia Kumacheva, Jacob Klein

Affiliation

¹ Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK.

PMID: 16800669
DOI: 10.1021/la053097h

Abstract

We have measured normal and lateral interactions across a range of different liquids between mica surfaces using a surface force balance (SFB). The mica surfaces were prepared either by melt cutting using Pt wire and standard procedures in our laboratories or by tearing sheets (that had not been exposed to Pt) off from a freshly cleaved sheet of mica. AFM micrographs revealed the substantial absence of Pt nanoparticles on the melt cut and torn-off mica surfaces. Normal-force versus surface-separation (D) profiles and shear force versus D measurements for purified water (no added salt), for concentrated aqueous NaCl solutions, and for cyclohexane revealed that in all cases the behavior of the highly confined liquids between melt-cut and between torn-off mica sheets was identical within experimental scatter. These results demonstrate directly that interactions measured between melt-cut mica surfaces as routinely prepared using established procedures in our laboratories and in other laboratories are free of the effect of any Pt contamination.