Archimedes’ principle states that the weight of a submerged body is reduced by the weight of the fluid it displaces, implying that buoyancy can be described fully in terms of geometry and physics. In our Small article we show that porous nanoparticles can violate this assertion. Direct weighing of porous Metal-organic framework (MOF) nanoparticles in different binary solvents using nanomechanical Mass Correlation Spectroscopy (MCS) reveals that the apparent mass density of these particles exhibits a pronounced dependence on the chemical identity of the solvent molecules. Interestingly, the pore size of the nanoparticles is much too large for the exclusion of small solvent molecules by steric hindrance. Although MOF materials are known for their selective binding of molecules in the gas phase, selective permeation to different solvent components has not previously been measured. Our findings suggest that the interactions between the solvent components and the internal MOF surface create a complex partitioning pattern, which may substantially differ from the solvent composition.
http://wuttkescience.com/wp-content/uploads/2018/06/violation_archimedes.jpg 1500 1500 pfabian http://wuttke.pfabian.de/wp-content/uploads/2018/07/wuttke_group_logo_auf_weiss-300x89.png pfabian2018-06-19 23:11:072018-10-31 22:04:48Violation of Archimedes’ Principle in Metal-Organic Framework Nanoparticles