Intersurface Forces and Dissolution of Minerals At Contact Points

The overall theme of my research is to understand the molecular and nanoparticle behavior at the interface of surfaces. Important parts of advancing in this direction are to develope and implement new experimental devices [1] for interfacial science in general and integrate them into a Surface Forces Apparatus [2] in particular. As the size of particles reaches characteristic length scales, novel physical properties (compare to bulk properties) start to emerge [3]. The carbon nanotubes are one candidate and I will present a study of the interactive forces in aqueous films of carbon nanotubes on mica surfaces at nanometer scale.

Control and understanding of dissolution processes are of critical importance in various areas such as corrosion, chemical mechanical polishing (CMP) and geology. Despite the apparent importance of electrochemical reactions in the dissolution process [4], very little is known about the relationship between surface potentials, overlapping electric double layers at the contact between dissimilar minerals, and dissolution rates; primarily due to the lack of experimental setups, which can visualize and measure dissolution rates in-situ between two closely apposed mineral surfaces in real time with atomic scale resolution. We have developed a new electrochemical Surface Forces Apparatus and I will present results of dissolution of amorphous quartz as function of applied potential on an apposing gold surface, which shows dissolution in the range of nanometers per hour [5].

 [1]       Kristiansen K, McGuiggan P M, Carver G, Meinhart C, and Israelachvili J; “3D Force and Displacement Sensor for AFM and SFA measurements”. Langmuir 24 (2008) 1541-1549.

[2]        Israelachvili J, Min Y, Akbulut M, Alig A, Carver G, Greene G W, Kristiansen K, Meyer E E, Pesika N, Rosenberg K, and Zeng H; “Recent advances in the surface forces apparatus (SFA) technique”. Reports on Progress in Physics 73 (2010) 036601.

[3]        Min Y J, Akbulut M, Kristiansen K, Golan Y, and Israelachvili J; “The role of interparticle and external forces in nanoparticle assembly”. Nature Materials 7 (2008) 527-538.

[4]        Greene G W, Kristiansen K, Meyer E E, Boles J, and Israelachvili J; “Role of electrochemical reactions in pressure solution“, Geochimica et Cormochimica Acta 73 (2009) 2862-2874.

[5]       Kristiansen K, Valtiner M, Greene G W, Boles J, and Israelachvili J; “Pressure solution – the importance of the electrochemical surface potentials”, submitted to Geochimica et Cosmochimica Acta.