Method and Apparatus for Determining Liquid-Solid Adhesion Work

An apparatus for determining liquid-solid adhesion work, comprising

• a measurement element having an end portion having peripheral circular edge for arranging the end portion thereof having peripheral circular edge in a fluid medium (6) together with a solid object to be tested having a surface (4) to be tested, wherein, in case of utilising the apparatus, the measurement element and the surface (4) to be tested are arranged with respect to each other such that a liquid cylindrically symmetric capillary bridge (9) can be formed between the end portion having peripheral circular edge and the surface (4) to be tested, the measurement element has a capillary conduction channel (14) opening to the end portion having peripheral circular edge,
• a liquid feeder (12), to which the end of the capillary conduction channel (14) opposite the end portion having peripheral circular edge is connected, and
• an interfacial area determination arrangement adapted for determining a first interfacial area of the capillary bridge (9) and the fluid medium (6), and a second interfacial area of the capillary bridge (9) and the surface (4) to be tested,
• characterised in that the liquid feeder (12) is adapted for performing a cylindrical symmetry-keeping modification on the cylindrically symmetric capillary bridge (9) by passing the liquid through the capillary conduction channel (14), the apparatus further comprising
• a displacement determination unit adapted for determining in the course of the cylindrical symmetry-keeping modification at least one displacement value of the working-related displacement, corresponding to the cylindrical symmetry-keeping modification, of the liquid in the capillary conduction channel (14),
• a force measurer (2) adapted for determining a force value of a capillary force corresponding to the capillary bridge (9) for the at least one displacement value,
• an integrator unit (10) adapted for determining a total mechanical work corresponding to the capillary force for the cylindrical symmetry-keeping modification based on the at least one displacement value determined by means of the displacement determination unit in the course of the cylindrical symmetry-keeping modification and the force value assigned respectively thereto, and
• a work determination unit adapted for determining, for the cylindrical symmetry-keeping modification,
• based on a first interfacial area change and a second interfacial area change of the first interfacial area and the second interfacial area, respectively, determined by the interfacial area determination arrangement between the initial state and the final state of the cylindrically symmetric capillary bridge (9), on the total mechanical work, and on a liquid-fluid interfacial tension of the capillary bridge (9) and the fluid medium (6), a first difference value of
• a solid-liquid interfacial tension of the surface (4) to be tested and the capillary bridge (9) and
• a solid-fluid interfacial tension of the surface (4) to be tested and the fluid medium (6), and
• by subtracting the first difference value from the liquid-fluid interfacial tension, a liquid-solid adhesion work corresponding to the cylindrical symmetry-keeping modification and being characteristic of the capillary bridge (9) and the surface (4) to be tested.