“So far the scientific community has assumed that an obstacle smaller than one nanometer is too weak to stop a liquid. Our calculations refute that,” Dr. Lothar Schimmele explains.
The results of these studies can be used to explain another phenomenon as well. Tiny gas bubbles which form on surfaces, for example during catalysis or electrolysis, often have an unexpectedly long lifespan. However, these gas bubbles reduce the effectiveness of electrolysis processes and disturb them.
The pinning of a gas bubble on the surface prevents the continuous increase of pressure in the bubble, thereby stabilizing it. Pinning can be explained by the observations of the Dietrich research group: It is caused by irregularities on the surface in the range of a few nanometers.
The insights gained through this work can also be of importance for other practical applications. One example is the use of liquid bridges for the artificial assembly of nanostructures. Nanoparticles are positioned and oriented with the help of these bridges. Once again pinning on irregularities plays an important role.
The scientists have already set additional goals for themselves: They want to investigate various types of irregularities on surfaces in order to find out what respective influence the material composition or geometric shape of an irregularity in the nanometer range has on stopping a drop of liquid.
The researchers are interested in collective phenomena as well. “Next we want to investigate the influence of multiple defects which are close to each other forming a group. We are also interested in the flow behavior of liquids across obstacles in the form of surface holes, rather than the bumps studied so far,” Dr. Lothar Schimmele explains.